Merge bbce13d538 into 83e211fed7

* Prepare to use Java 17 as minimal version

* See #6219 Pattern Matching for instanceof uses (Java 14/16)

* See #6219 - Implicit Typing with var (Java 10)

* See #6219 - Using Switch Expressions / yield Keyword (Java 14)

* See #6219 - Using Text Blocks (Java 15)

* See #6219 - some tunning / formating style

* See #6219 - tunning code

* See #6219 - Update Java argline params / remove java 8 / 9 args/comments

* See #6219 - formating code

* Remove not standard options for Java 17

* See #6219 - refactor CompOper to an enum

* See #6219 - fix unnecessary yield usage in the switch expression

* See #6219 - Optimize the code, fix formatting issue

bin/jmeter

@@ -115,18 +115,19 @@ if [ -z "$JAVA_HOME" ]; then
   JAVA_HOME="$JRE_HOME"
 fi
 
-#--add-opens if JAVA 9
-JAVA9_OPTS=
+# Module access for modern Java versions (required for JMeter components)
+JAVA_OPTS="--add-opens java.desktop/sun.awt=ALL-UNNAMED --add-opens java.desktop/sun.swing=ALL-UNNAMED --add-opens java.desktop/javax.swing.text.html=ALL-UNNAMED --add-opens java.desktop/java.awt=ALL-UNNAMED --add-opens java.desktop/java.awt.font=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.lang.reflect=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.text=ALL-UNNAMED --add-opens=java.desktop/sun.awt.X11=ALL-UNNAMED --add-opens=java.desktop/sun.awt.shell=ALL-UNNAMED"
 
 # Minimal version to run JMeter
-MINIMAL_VERSION=8
+MINIMAL_VERSION=17
 
-# Check if version is from OpenJDK or Oracle Hotspot JVM prior to 9 containing 1.${version}.x
+# Check if version meets the minimal requirement
 CURRENT_VERSION=`"${JAVA_HOME}/bin/java" -version 2>&1 | awk -F'"' '/version/ {gsub("^1[.]", "", $2); gsub("[^0-9].*$", "", $2); print $2}'`
 
-# Check if Java is present and the minimal version requirement
-if [ "$CURRENT_VERSION" -gt "$MINIMAL_VERSION" ]; then
-    JAVA9_OPTS="--add-opens java.desktop/sun.awt=ALL-UNNAMED --add-opens java.desktop/sun.swing=ALL-UNNAMED --add-opens java.desktop/javax.swing.text.html=ALL-UNNAMED --add-opens java.desktop/java.awt=ALL-UNNAMED --add-opens java.desktop/java.awt.font=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.lang.reflect=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.text=ALL-UNNAMED --add-opens=java.desktop/sun.awt.X11=ALL-UNNAMED --add-opens=java.desktop/sun.awt.shell=ALL-UNNAMED"
+# Check if Java is present and meets the minimal version requirement
+if [ "$CURRENT_VERSION" -lt "$MINIMAL_VERSION" ]; then
+    echo "ERROR: Java version $CURRENT_VERSION is too low. JMeter requires Java $MINIMAL_VERSION or higher."
+    exit 1
 fi
 
 : "${JMETER_OPTS:=""}"
@@ -169,15 +170,19 @@ esac
 # Default to en_EN
 : "${JMETER_LANGUAGE:="-Duser.language=en -Duser.region=EN"}"
 
-# Uncomment this to generate GC verbose file with Java prior to 9
-# VERBOSE_GC="-verbose:gc -Xloggc:gc_jmeter_%p.log -XX:+PrintGCDetails -XX:+PrintGCCause -XX:+PrintTenuringDistribution -XX:+PrintHeapAtGC -XX:+PrintGCApplicationConcurrentTime -XX:+PrintAdaptiveSizePolicy -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDateStamps"
+# Legacy GC verbose options removed (Java 8/9 support discontinued)
 
-# Uncomment this to generate GC verbose file with Java 9 and above
-# VERBOSE_GC="-Xlog:gc*,gc+age=trace,gc+heap=debug:file=gc_jmeter_%p.log"
+# Optimized GC logging for Java 17 with structured output and performance analysis
+# Uncomment to enable comprehensive GC logging with rotation and detailed metrics
+# VERBOSE_GC="-Xlog:gc,gc+heap,gc+regions,gc+refine,gc+phases:gc_jmeter_%p_%t.log:time,level,tags:filecount=5,filesize=50M"
+
+# Alternative: Minimal GC logging for production (uncomment if needed)
+# VERBOSE_GC="-Xlog:gc:gc_jmeter_%p.log:time"
+
+# Docker support for Java 17+
+# Modern container memory detection is automatic in Java 17+
+# RUN_IN_DOCKER="-XX:+UseContainerSupport"
 
-# Uncomment this if you run JMeter in DOCKER (need Java SE 8u131 or JDK 9)
-# see https://blogs.oracle.com/java-platform-group/java-se-support-for-docker-cpu-and-memory-limits
-# RUN_IN_DOCKER="-XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap"
 
 # Finally, some tracing to help in case things go astray:
 # You may want to add those settings:
@@ -191,7 +196,7 @@ SYSTEM_PROPS="-Djava.security.egd=file:/dev/urandom"
 SERVER="-server"
 
 if [ -z "${JMETER_COMPLETE_ARGS}" ]; then
-    ARGS="$JAVA9_OPTS $SERVER $DUMP $HEAP $VERBOSE_GC $GC_ALGO $SYSTEM_PROPS $JMETER_LANGUAGE $RUN_IN_DOCKER"
+    ARGS="$JAVA_OPTS $SERVER $DUMP $HEAP $VERBOSE_GC $GC_ALGO $SYSTEM_PROPS $JMETER_LANGUAGE $RUN_IN_DOCKER"
 else
     ARGS=""
 fi

bin/jmeter.bat

@@ -78,12 +78,19 @@ if not defined JMETER_LANGUAGE (
 )
 
 rem Minimal version to run JMeter
-set MINIMAL_VERSION=1.8.0
+set MINIMAL_VERSION=17.0.0
 
 
-rem --add-opens if JAVA 9
-set JAVA9_OPTS=
+rem Optimized GC logging for Java 17 with structured output and performance analysis
+rem Uncomment to enable comprehensive GC logging with rotation and detailed metrics
+rem set VERBOSE_GC=-Xlog:gc,gc+heap,gc+regions,gc+refine,gc+phases:gc_jmeter_%%p_%%t.log:time,level,tags:filecount=5,filesize=50M
 
+rem Alternative: Minimal GC logging for production (uncomment if needed)
+rem set VERBOSE_GC=-Xlog:gc:gc_jmeter_%%p.log:time
+
+
+rem Module access for modern Java versions (required for JMeter components)
+set JAVA_OPTS=--add-opens java.desktop/sun.awt=ALL-UNNAMED --add-opens java.desktop/sun.swing=ALL-UNNAMED --add-opens java.desktop/javax.swing.text.html=ALL-UNNAMED --add-opens java.desktop/java.awt=ALL-UNNAMED --add-opens java.desktop/java.awt.font=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.lang.reflect=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.text=ALL-UNNAMED --add-opens=java.desktop/sun.awt.shell=ALL-UNNAMED
 
 for /f "tokens=3" %%g in ('java -version 2^>^&1 ^| findstr /i "version"') do (
     rem @echo Debug Output: %%g
@@ -95,36 +102,24 @@ if not defined JAVAVER (
     goto pause
 )
 
-
-
-rem Check if version is from OpenJDK or Oracle Hotspot JVM prior to 9 containing 1.${version}.x
-rem JAVAVER will be equal to "9.0.4" (quotes are part of the value) for Oracle Java 9
-rem JAVAVER will be equal to "1.8.0_161" (quotes are part of the value) for Oracle Java 8
-rem so we extract 2 chars starting from index 1
-IF "%JAVAVER:~1,2%"=="1." (
-    set JAVAVER=%JAVAVER:"=%
-    for /f "delims=. tokens=1-3" %%v in ("%JAVAVER%") do (
-        set current_minor=%%w
-)
-) else (
-    rem Java 9 at least
-    set current_minor=9
-    set JAVA9_OPTS=--add-opens java.desktop/sun.awt=ALL-UNNAMED --add-opens java.desktop/sun.swing=ALL-UNNAMED --add-opens java.desktop/javax.swing.text.html=ALL-UNNAMED --add-opens java.desktop/java.awt=ALL-UNNAMED --add-opens java.desktop/java.awt.font=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.lang.reflect=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.text=ALL-UNNAMED --add-opens=java.desktop/sun.awt.shell=ALL-UNNAMED
+rem Extract major version number from Java version string
+for /f "delims=. tokens=1" %%v in ("%JAVAVER:~1,-1%") do (
+    set current_major=%%v
 )
 
-
-for /f "delims=. tokens=1-3" %%v in ("%MINIMAL_VERSION%") do (
-    set minimal_minor=%%w
+rem Extract minimal major version
+for /f "delims=. tokens=1" %%v in ("%MINIMAL_VERSION%") do (
+    set minimal_major=%%v
 )
 
-if not defined current_minor (
+if not defined current_major (
     @echo Not able to find Java executable or version. Please check your Java installation.
     set ERRORLEVEL=2
     goto pause
 )
-rem @echo Debug: CURRENT=%current_minor% - MINIMAL=%minimal_minor%
-if %current_minor% LSS %minimal_minor% (
-    @echo Error: Java version -- %JAVAVER% -- is too low to run JMeter. Needs a Java version greater than or equal to %MINIMAL_VERSION%
+
+if %current_major% LSS %minimal_major% (
+    @echo Error: Java version -- %JAVAVER% -- is too low to run JMeter. Needs Java %MINIMAL_VERSION% or higher.
     set ERRORLEVEL=3
     goto pause
 )
@@ -151,13 +146,7 @@ if not defined HEAP (
     set HEAP=-Xms1g -Xmx1g -XX:MaxMetaspaceSize=256m
 )
 
-rem Uncomment this to generate GC verbose file with Java prior to 9
-rem set VERBOSE_GC=-verbose:gc -Xloggc:gc_jmeter_%%p.log -XX:+PrintGCDetails -XX:+PrintGCCause -XX:+PrintTenuringDistribution -XX:+PrintHeapAtGC -XX:+PrintGCApplicationConcurrentTime -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDateStamps -XX:+PrintAdaptiveSizePolicy
-
-rem Uncomment this to generate GC verbose file with Java 9 and above
-rem set VERBOSE_GC=-Xlog:gc*,gc+age=trace,gc+heap=debug:file=gc_jmeter_%%p.log
-rem You may want to add those settings
-rem -XX:+ParallelRefProcEnabled -XX:+PerfDisableSharedMem
+rem Legacy GC verbose options removed (Java 8/9 support discontinued)
 if not defined GC_ALGO (
     set GC_ALGO=-XX:+UseG1GC -XX:MaxGCPauseMillis=100 -XX:G1ReservePercent=20
 )
@@ -167,9 +156,9 @@ set SYSTEM_PROPS=-Djava.security.egd=file:/dev/urandom
 rem Always dump on OOM (does not cost anything unless triggered)
 set DUMP=-XX:+HeapDumpOnOutOfMemoryError
 
-rem Uncomment this if you run JMeter in DOCKER (need Java SE 8u131 or JDK 9)
-rem see https://blogs.oracle.com/java-platform-group/java-se-support-for-docker-cpu-and-memory-limits
-rem set RUN_IN_DOCKER=-XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap
+rem Docker support for Java 17+
+rem Modern container memory detection is automatic in Java 17+
+rem set RUN_IN_DOCKER=-XX:+UseContainerSupport
 
 rem Additional settings that might help improve GUI performance on some platforms
 rem See: http://www.oracle.com/technetwork/java/perf-graphics-135933.html
@@ -188,7 +177,7 @@ if not defined DDRAW (
 
 rem Collect the settings defined above
 if not defined JMETER_COMPLETE_ARGS (
-    set ARGS=%JAVA9_OPTS% %DUMP% %HEAP% %VERBOSE_GC% %GC_ALGO% %DDRAW% %SYSTEM_PROPS% %JMETER_LANGUAGE% %RUN_IN_DOCKER%
+    set ARGS=%JAVA_OPTS% %DUMP% %HEAP% %VERBOSE_GC% %GC_ALGO% %DDRAW% %SYSTEM_PROPS% %JMETER_LANGUAGE% %RUN_IN_DOCKER%
 ) else (
     set ARGS=
 )

bin/jmeter.sh

@@ -90,14 +90,17 @@ fi
 JAVA9_OPTS=
 
 # Minimal version to run JMeter
-MINIMAL_VERSION=8
+MINIMAL_VERSION=17
 
 # Check if version is from OpenJDK or Oracle Hotspot JVM prior to 9 containing 1.${version}.x
 CURRENT_VERSION=`"${JAVA_HOME}/bin/java" -version 2>&1 | awk -F'"' '/version/ {gsub("^1[.]", "", $2); gsub("[^0-9].*$", "", $2); print $2}'`
 
 # Check if Java is present and the minimal version requirement
-if [ "$CURRENT_VERSION" -gt "$MINIMAL_VERSION" ]; then
+if [ "$CURRENT_VERSION" -ge "$MINIMAL_VERSION" ]; then
     JAVA9_OPTS="--add-opens java.desktop/sun.awt=ALL-UNNAMED --add-opens java.desktop/sun.swing=ALL-UNNAMED --add-opens java.desktop/javax.swing.text.html=ALL-UNNAMED --add-opens java.desktop/java.awt=ALL-UNNAMED --add-opens java.desktop/java.awt.font=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.lang.reflect=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.text=ALL-UNNAMED --add-opens=java.desktop/sun.awt.X11=ALL-UNNAMED --add-opens=java.desktop/sun.awt.shell=ALL-UNNAMED"
+else
+    echo "JMeter requires Java $MINIMAL_VERSION or later. Current Java version is $CURRENT_VERSION"
+    exit 1
 fi
 
 # Don't add additional arguments to the JVM start, except those needed for Java 9

build-logic/jvm/src/main/kotlin/build-logic.java.gradle.kts

@@ -121,18 +121,14 @@ tasks.configureEach<Javadoc> {
         docTitle = "Apache JMeter ${project.name} API"
         windowTitle = "Apache JMeter ${project.name} API"
         header = "<b>Apache JMeter</b>"
-        addStringOption("source", "8")
+        addStringOption("source", "17")
         addStringOption("Xmaxwarns", "10")
         addBooleanOption("Xdoclint:all,-missing", true)
         val lastEditYear: String by rootProject.extra
         bottom =
             "Copyright &copy; 1998-$lastEditYear Apache Software Foundation. All Rights Reserved."
-        if (buildParameters.buildJdkVersion > 8) {
-            addBooleanOption("html5", true)
-            links("https://docs.oracle.com/en/java/javase/11/docs/api/")
-        } else {
-            links("https://docs.oracle.com/javase/8/docs/api/")
-        }
+        addBooleanOption("html5", true)
+        links("https://docs.oracle.com/en/java/javase/17/docs/api/")
     }
 }
 

src/components/src/main/java/org/apache/jmeter/assertions/SizeAssertion.java

@@ -35,17 +35,86 @@ public class SizeAssertion extends AbstractScopedAssertion implements Serializab
 
     private static final long serialVersionUID = 241L;
 
-    // Static int to signify the type of logical comparator to assert
+    /**
+     * Comparison operators for size assertions
+     */
+    public enum ComparisonOperator {
+        EQUAL(1, "size_assertion_comparator_error_equal"),
+        NOTEQUAL(2, "size_assertion_comparator_error_notequal"),
+        GREATERTHAN(3, "size_assertion_comparator_error_greater"),
+        LESSTHAN(4, "size_assertion_comparator_error_less"),
+        GREATERTHANEQUAL(5, "size_assertion_comparator_error_greaterequal"),
+        LESSTHANEQUAL(6, "size_assertion_comparator_error_lessequal");
+
+        private static final ComparisonOperator[] VALUES = values();
+
+        private final int value;
+        private final String errorMessageKey;
+
+        ComparisonOperator(int value, String errorMessageKey) {
+            this.value = value;
+            this.errorMessageKey = errorMessageKey;
+        }
+
+        public int getValue() {
+            return value;
+        }
+
+        public String getErrorMessageKey() {
+            return errorMessageKey;
+        }
+
+        public static ComparisonOperator fromValue(int value) {
+            for (ComparisonOperator op : VALUES) {
+                if (op.value == value) {
+                    return op;
+                }
+            }
+            return null;
+        }
+
+        public boolean evaluate(long actual, long expected) {
+            switch (this) {
+                case EQUAL:
+                    return actual == expected;
+                case NOTEQUAL:
+                    return actual != expected;
+                case GREATERTHAN:
+                    return actual > expected;
+                case LESSTHAN:
+                    return actual < expected;
+                case GREATERTHANEQUAL:
+                    return actual >= expected;
+                case LESSTHANEQUAL:
+                    return actual <= expected;
+            }
+            throw new IllegalStateException("Unexpected value: " + this);
+        }
+    }
+
+    // Backward compatibility constants - deprecated
+    /** @deprecated Use {@link ComparisonOperator#EQUAL} instead */
+    @Deprecated
     public static final int EQUAL = 1;
 
+    /** @deprecated Use {@link ComparisonOperator#NOTEQUAL} instead */
+    @Deprecated
     public static final int NOTEQUAL = 2;
 
+    /** @deprecated Use {@link ComparisonOperator#GREATERTHAN} instead */
+    @Deprecated
     public static final int GREATERTHAN = 3;
 
+    /** @deprecated Use {@link ComparisonOperator#LESSTHAN} instead */
+    @Deprecated
     public static final int LESSTHAN = 4;
 
+    /** @deprecated Use {@link ComparisonOperator#GREATERTHANEQUAL} instead */
+    @Deprecated
     public static final int GREATERTHANEQUAL = 5;
 
+    /** @deprecated Use {@link ComparisonOperator#LESSTHANEQUAL} instead */
+    @Deprecated
     public static final int LESSTHANEQUAL = 6;
 
     /** Key for storing assertion-information in the jmx-file. */
@@ -175,41 +244,17 @@ public class SizeAssertion extends AbstractScopedAssertion implements Serializab
      *
      */
     private String compareSize(long resultSize) {
-        String comparatorErrorMessage;
         long allowedSize = Long.parseLong(getAllowedSize());
-        boolean result;
-        int comp = getCompOper();
-        switch (comp) {
-        case EQUAL:
-            result = resultSize == allowedSize;
-            comparatorErrorMessage = JMeterUtils.getResString("size_assertion_comparator_error_equal"); //$NON-NLS-1$
-            break;
-        case NOTEQUAL:
-            result = resultSize != allowedSize;
-            comparatorErrorMessage = JMeterUtils.getResString("size_assertion_comparator_error_notequal"); //$NON-NLS-1$
-            break;
-        case GREATERTHAN:
-            result = resultSize > allowedSize;
-            comparatorErrorMessage = JMeterUtils.getResString("size_assertion_comparator_error_greater"); //$NON-NLS-1$
-            break;
-        case LESSTHAN:
-            result = resultSize < allowedSize;
-            comparatorErrorMessage = JMeterUtils.getResString("size_assertion_comparator_error_less"); //$NON-NLS-1$
-            break;
-        case GREATERTHANEQUAL:
-            result = resultSize >= allowedSize;
-            comparatorErrorMessage = JMeterUtils.getResString("size_assertion_comparator_error_greaterequal"); //$NON-NLS-1$
-            break;
-        case LESSTHANEQUAL:
-            result = resultSize <= allowedSize;
-            comparatorErrorMessage = JMeterUtils.getResString("size_assertion_comparator_error_lessequal"); //$NON-NLS-1$
-            break;
-        default:
-            result = false;
-            comparatorErrorMessage = "ERROR - invalid condition";
-            break;
+        ComparisonOperator operator = ComparisonOperator.fromValue(getCompOper());
+        if (operator == null) {
+            return "ERROR - invalid condition";
+        }
+        
+        if (operator.evaluate(resultSize, allowedSize)) {
+            return "";
+        } else {
+            return JMeterUtils.getResString(operator.getErrorMessageKey());
         }
-        return result ? "" : comparatorErrorMessage;
     }
 
     private void setTestField(String testField) {

src/components/src/main/java/org/apache/jmeter/assertions/gui/SizeAssertionGui.java

@@ -135,7 +135,7 @@ public class SizeAssertionGui extends AbstractAssertionGui implements ActionList
         lessthanButton.setSelected(false);
         greaterthanequalButton.setSelected(false);
         lessthanequalButton.setSelected(false);
-        execState = SizeAssertion.EQUAL;
+        execState = SizeAssertion.ComparisonOperator.EQUAL.getValue();
     }
 
     @Override
@@ -164,32 +164,32 @@ public class SizeAssertionGui extends AbstractAssertionGui implements ActionList
      * <p>
      * Allowed states are
      * <ul>
-     * <li>{@link SizeAssertion#EQUAL}</li>
-     * <li>{@link SizeAssertion#NOTEQUAL}</li>
-     * <li>{@link SizeAssertion#GREATERTHAN}</li>
-     * <li>{@link SizeAssertion#LESSTHAN}</li>
-     * <li>{@link SizeAssertion#GREATERTHANEQUAL}</li>
-     * <li>{@link SizeAssertion#LESSTHANEQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#EQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#NOTEQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#GREATERTHAN}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#LESSTHAN}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#GREATERTHANEQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#LESSTHANEQUAL}</li>
      * </ul>
      * @param state One of the allowed states
      */
     public void setState(int state) {
-        if (state == SizeAssertion.EQUAL) {
+        if (state == SizeAssertion.ComparisonOperator.EQUAL.getValue()) {
             equalButton.setSelected(true);
             execState = state;
-        } else if (state == SizeAssertion.NOTEQUAL) {
+        } else if (state == SizeAssertion.ComparisonOperator.NOTEQUAL.getValue()) {
             notequalButton.setSelected(true);
             execState = state;
-        } else if (state == SizeAssertion.GREATERTHAN) {
+        } else if (state == SizeAssertion.ComparisonOperator.GREATERTHAN.getValue()) {
             greaterthanButton.setSelected(true);
             execState = state;
-        } else if (state == SizeAssertion.LESSTHAN) {
+        } else if (state == SizeAssertion.ComparisonOperator.LESSTHAN.getValue()) {
             lessthanButton.setSelected(true);
             execState = state;
-        } else if (state == SizeAssertion.GREATERTHANEQUAL) {
+        } else if (state == SizeAssertion.ComparisonOperator.GREATERTHANEQUAL.getValue()) {
             greaterthanequalButton.setSelected(true);
             execState = state;
-        } else if (state == SizeAssertion.LESSTHANEQUAL) {
+        } else if (state == SizeAssertion.ComparisonOperator.LESSTHANEQUAL.getValue()) {
             lessthanequalButton.setSelected(true);
             execState = state;
         }
@@ -200,12 +200,12 @@ public class SizeAssertionGui extends AbstractAssertionGui implements ActionList
      * <p>
      * Possible states are
      * <ul>
-     * <li>{@link SizeAssertion#EQUAL}</li>
-     * <li>{@link SizeAssertion#NOTEQUAL}</li>
-     * <li>{@link SizeAssertion#GREATERTHAN}</li>
-     * <li>{@link SizeAssertion#LESSTHAN}</li>
-     * <li>{@link SizeAssertion#GREATERTHANEQUAL}</li>
-     * <li>{@link SizeAssertion#LESSTHANEQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#EQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#NOTEQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#GREATERTHAN}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#LESSTHAN}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#GREATERTHANEQUAL}</li>
+     * <li>{@link SizeAssertion.ComparisonOperator#LESSTHANEQUAL}</li>
      * </ul>
      * @return The current state of the radio Button
      */
@@ -273,12 +273,12 @@ public class SizeAssertionGui extends AbstractAssertionGui implements ActionList
     private Box createComparatorButtonPanel() {
         ButtonGroup group = new ButtonGroup();
 
-        equalButton = createComparatorButton("=", SizeAssertion.EQUAL, group); //$NON-NLS-1$
-        notequalButton = createComparatorButton("!=", SizeAssertion.NOTEQUAL, group); //$NON-NLS-1$
-        greaterthanButton = createComparatorButton(">", SizeAssertion.GREATERTHAN, group); //$NON-NLS-1$
-        lessthanButton = createComparatorButton("<", SizeAssertion.LESSTHAN, group); //$NON-NLS-1$
-        greaterthanequalButton = createComparatorButton(">=", SizeAssertion.GREATERTHANEQUAL, group); //$NON-NLS-1$
-        lessthanequalButton = createComparatorButton("<=", SizeAssertion.LESSTHANEQUAL, group); //$NON-NLS-1$
+        equalButton = createComparatorButton("=", SizeAssertion.ComparisonOperator.EQUAL.getValue(), group); //$NON-NLS-1$
+        notequalButton = createComparatorButton("!=", SizeAssertion.ComparisonOperator.NOTEQUAL.getValue(), group); //$NON-NLS-1$
+        greaterthanButton = createComparatorButton(">", SizeAssertion.ComparisonOperator.GREATERTHAN.getValue(), group); //$NON-NLS-1$
+        lessthanButton = createComparatorButton("<", SizeAssertion.ComparisonOperator.LESSTHAN.getValue(), group); //$NON-NLS-1$
+        greaterthanequalButton = createComparatorButton(">=", SizeAssertion.ComparisonOperator.GREATERTHANEQUAL.getValue(), group); //$NON-NLS-1$
+        lessthanequalButton = createComparatorButton("<=", SizeAssertion.ComparisonOperator.LESSTHANEQUAL.getValue(), group); //$NON-NLS-1$
 
         equalButton.setSelected(true);
         execState = Integer.parseInt(equalButton.getActionCommand());

src/components/src/main/java/org/apache/jmeter/config/CSVDataSet.java

@@ -222,20 +222,12 @@ public class CSVDataSet extends ConfigTestElement
     private void setAlias(final JMeterContext context, String alias) {
         String mode = getShareMode();
         int modeInt = CSVDataSetBeanInfo.getShareModeAsInt(mode);
-        switch(modeInt){
-            case CSVDataSetBeanInfo.SHARE_ALL:
-                this.alias = alias;
-                break;
-            case CSVDataSetBeanInfo.SHARE_GROUP:
-                this.alias = alias + "@" + System.identityHashCode(context.getThreadGroup());
-                break;
-            case CSVDataSetBeanInfo.SHARE_THREAD:
-                this.alias = alias + "@" + System.identityHashCode(context.getThread());
-                break;
-            default:
-                this.alias = alias + "@" + mode; // user-specified key
-                break;
-        }
+        this.alias = switch(modeInt){
+            case CSVDataSetBeanInfo.SHARE_ALL -> alias;
+            case CSVDataSetBeanInfo.SHARE_GROUP -> alias + "@" + System.identityHashCode(context.getThreadGroup());
+            case CSVDataSetBeanInfo.SHARE_THREAD -> alias + "@" + System.identityHashCode(context.getThread());
+            default -> alias + "@" + mode; // user-specified key
+        };
     }
 
     /**

src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONPostProcessor.java

@@ -157,12 +157,12 @@ public class JSONPostProcessor
         if (matchNumber < 0) {
             // Extract all
             int index = 1;
-            StringBuilder concat =
+            var concat =
                     new StringBuilder(getComputeConcatenation()
                             ? extractedValues.size() * 20
                             : 1);
             for (Object extractedObject : extractedValues) {
-                String extractedString = Objects.toString(extractedObject, defaultValue);
+                var extractedString = Objects.toString(extractedObject, defaultValue);
                 vars.put(currentRefName + "_" + index,
                         extractedString); //$NON-NLS-1$
                 if (getComputeConcatenation()) {

src/components/src/main/java/org/apache/jmeter/sampler/gui/TestActionGui.java

@@ -114,26 +114,13 @@ public class TestActionGui extends AbstractSamplerGui { // NOSONAR Ignore hierar
         }
         action = ta.getAction();
         switch (action) {
-            case TestAction.PAUSE:
-                pauseButton.setSelected(true);
-                break;
-            case TestAction.STOP_NOW:
-                stopNowButton.setSelected(true);
-                break;
-            case TestAction.STOP:
-                stopButton.setSelected(true);
-                break;
-            case TestAction.RESTART_NEXT_LOOP:
-                restartNextThreadLoopButton.setSelected(true);
-                break;
-            case TestAction.START_NEXT_ITERATION_CURRENT_LOOP:
-                startNextIterationOfCurrentLoopButton.setSelected(true);
-                break;
-            case TestAction.BREAK_CURRENT_LOOP:
-                breakLoopButton.setSelected(true);
-                break;
-            default:
-                break;
+            case TestAction.PAUSE -> pauseButton.setSelected(true);
+            case TestAction.STOP_NOW -> stopNowButton.setSelected(true);
+            case TestAction.STOP -> stopButton.setSelected(true);
+            case TestAction.RESTART_NEXT_LOOP -> restartNextThreadLoopButton.setSelected(true);
+            case TestAction.START_NEXT_ITERATION_CURRENT_LOOP -> startNextIterationOfCurrentLoopButton.setSelected(true);
+            case TestAction.BREAK_CURRENT_LOOP -> breakLoopButton.setSelected(true);
+            default -> { /* no action needed */ }
         }
 
         durationField.setText(ta.getDurationAsString());

src/components/src/main/java/org/apache/jmeter/visualizers/ViewResultsFullVisualizer.java

@@ -546,12 +546,14 @@ implements ActionListener, TreeSelectionListener, Clearable, ItemListener {
             // they are ready to wait.
             int len = res.getResponseDataAsString().length();
             if (MAX_DISPLAY_SIZE > 0 && len > MAX_DISPLAY_SIZE) {
-                StringBuilder builder = new StringBuilder(MAX_DISPLAY_SIZE + 100);
-                builder.append(JMeterUtils.getResString("view_results_response_too_large_message")) //$NON-NLS-1$
-                    .append(len).append(" > Max: ").append(MAX_DISPLAY_SIZE)
-                    .append(", ").append(JMeterUtils.getResString("view_results_response_partial_message")) // $NON-NLS-1$
-                    .append("\n").append(res.getResponseDataAsString(), 0, MAX_DISPLAY_SIZE).append("\n...");
-                response = builder.toString();
+                response = """
+                        %s%d > Max: %d, %s
+                        %s
+                        ...""".formatted(
+                            JMeterUtils.getResString("view_results_response_too_large_message"), //$NON-NLS-1$
+                            len, MAX_DISPLAY_SIZE,
+                            JMeterUtils.getResString("view_results_response_partial_message"), // $NON-NLS-1$
+                            res.getResponseDataAsString().substring(0, MAX_DISPLAY_SIZE));
             } else {
                 response = res.getResponseDataAsString();
             }

src/components/src/main/java/org/apache/jmeter/visualizers/backend/SamplerMetric.java

@@ -178,15 +178,15 @@ public class SamplerMetric {
      */
     public synchronized void resetForTimeInterval() {
         switch (globalWindowMode) {
-        case FIXED:
-            // We don't clear responsesStats nor usersStats as it will slide as per my understanding of
-            // http://commons.apache.org/proper/commons-math/userguide/stat.html
-            break;
-        case TIMED:
-            for (DescriptiveStatistics stat : windowedStats) {
-                stat.clear();
+            case FIXED -> {
+                // We don't clear responsesStats nor usersStats as it will slide as per my understanding of
+                // http://commons.apache.org/proper/commons-math/userguide/stat.html
+            }
+            case TIMED -> {
+                for (DescriptiveStatistics stat : windowedStats) {
+                    stat.clear();
+                }
             }
-            break;
         }
         errors.clear();
         successes = 0;

src/components/src/test/java/org/apache/jmeter/assertions/SizeAssertionTest.java

@@ -55,7 +55,7 @@ public class SizeAssertionTest extends JMeterTestCase {
 
     @Test
     public void testSizeAssertionEquals() throws Exception {
-        assertion.setCompOper(SizeAssertion.EQUAL);
+        assertion.setCompOper(SizeAssertion.ComparisonOperator.EQUAL.getValue());
         assertion.setAllowedSize(0);
         result = assertion.getResult(sample1);
         assertFailed();
@@ -73,7 +73,7 @@ public class SizeAssertionTest extends JMeterTestCase {
 
     @Test
     public void testSizeAssertionNotEquals() throws Exception {
-        assertion.setCompOper(SizeAssertion.NOTEQUAL);
+        assertion.setCompOper(SizeAssertion.ComparisonOperator.NOTEQUAL.getValue());
         assertion.setAllowedSize(0);
         result = assertion.getResult(sample1);
         assertPassed();
@@ -91,7 +91,7 @@ public class SizeAssertionTest extends JMeterTestCase {
 
     @Test
     public void testSizeAssertionGreaterThan() throws Exception {
-        assertion.setCompOper(SizeAssertion.GREATERTHAN);
+        assertion.setCompOper(SizeAssertion.ComparisonOperator.GREATERTHAN.getValue());
         assertion.setAllowedSize(0);
         result = assertion.getResult(sample1);
         assertPassed();
@@ -109,7 +109,7 @@ public class SizeAssertionTest extends JMeterTestCase {
 
     @Test
     public void testSizeAssertionGreaterThanEqual() throws Exception {
-        assertion.setCompOper(SizeAssertion.GREATERTHANEQUAL);
+        assertion.setCompOper(SizeAssertion.ComparisonOperator.GREATERTHANEQUAL.getValue());
         assertion.setAllowedSize(0);
         result = assertion.getResult(sample1);
         assertPassed();
@@ -127,7 +127,7 @@ public class SizeAssertionTest extends JMeterTestCase {
 
     @Test
     public void testSizeAssertionLessThan() throws Exception {
-        assertion.setCompOper(SizeAssertion.LESSTHAN);
+        assertion.setCompOper(SizeAssertion.ComparisonOperator.LESSTHAN.getValue());
         assertion.setAllowedSize(0);
         result = assertion.getResult(sample1);
         assertFailed();
@@ -145,7 +145,7 @@ public class SizeAssertionTest extends JMeterTestCase {
 
     @Test
     public void testSizeAssertionLessThanEqual() throws Exception {
-        assertion.setCompOper(SizeAssertion.LESSTHANEQUAL);
+        assertion.setCompOper(SizeAssertion.ComparisonOperator.LESSTHANEQUAL.getValue());
         assertion.setAllowedSize(0);
         result = assertion.getResult(sample1);
         assertFailed();

src/components/src/test/java/org/apache/jmeter/extractor/TestJSONPostProcessor.java

@@ -86,8 +86,10 @@ class TestJSONPostProcessor {
         processor.setJsonPathExpressions(path);
         processor.setRefNames("result");
         accessMode.configure(processor);
-        SampleResult sampleResult = createSampleResult("{\"a\": 23, \"b\": \"parent_only\"}");
-        sampleResult.addSubResult(createSampleResult("{\"a\": 42, \"c\": \"child_only\"}"));
+        SampleResult sampleResult = createSampleResult("""
+                {"a": 23, "b": "parent_only"}""");
+        sampleResult.addSubResult(createSampleResult("""
+                {"a": 42, "c": "child_only"}"""));
         context.setPreviousResult(sampleResult);
         context.setVariables(vars);
         processor.process();
@@ -297,7 +299,8 @@ class TestJSONPostProcessor {
     void testExtractComplexElements() {
         JMeterContext context = JMeterContextService.getContext();
         JSONPostProcessor processor = setupProcessor(context, "-1");
-        String data = "[{\"a\":[1,{\"d\":2},3]},[\"b\",{\"h\":23}],3]";
+        String data = """
+                [{"a":[1,{"d":2},3]},["b",{"h":23}],3]""";
         SampleResult result = new SampleResult();
         result.setResponseData(data.getBytes(StandardCharsets.UTF_8));
         JMeterVariables vars = new JMeterVariables();
@@ -310,8 +313,10 @@ class TestJSONPostProcessor {
         String jsonWithoutOuterParens = data.substring(1, data.length() - 1);
         assertEquals(jsonWithoutOuterParens, vars.get(VAR_NAME + "_ALL"));
 
-        assertEquals("{\"a\":[1,{\"d\":2},3]}", vars.get(VAR_NAME + "_1"));
-        assertEquals("[\"b\",{\"h\":23}]", vars.get(VAR_NAME + "_2"));
+        assertEquals("""
+                {"a":[1,{"d":2},3]}""", vars.get(VAR_NAME + "_1"));
+        assertEquals("""
+                ["b",{"h":23}]""", vars.get(VAR_NAME + "_2"));
         assertEquals("3", vars.get(VAR_NAME + "_3"));
 
         assertEquals("3", vars.get(VAR_NAME + "_matchNr"));

src/core/src/main/java/org/apache/jmeter/config/Arguments.java

@@ -23,11 +23,13 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.collections4.iterators.FilterIterator;
 import org.apache.jmeter.testelement.property.CollectionProperty;
 import org.apache.jmeter.testelement.property.JMeterProperty;
 import org.apache.jmeter.testelement.property.PropertyIterator;
 import org.apache.jmeter.testelement.property.TestElementProperty;
 import org.apache.jmeter.testelement.schema.PropertiesAccessor;
+import org.apiguardian.api.API;
 
 /**
  * A set of Argument objects.
@@ -100,7 +102,7 @@ public class Arguments extends ConfigTestElement implements Serializable, Iterab
             // that this element's values prevail over defaults provided by
             // configuration
             // elements:
-            if (!argMap.containsKey(arg.getName())) {
+            if (!argMap.containsKey(arg.getName()) && arg.isEnabled()) {
                 argMap.put(arg.getName(), arg.getValue());
             }
         }
@@ -173,6 +175,18 @@ public class Arguments extends ConfigTestElement implements Serializable, Iterab
         return getArguments().iterator();
     }
 
+    /**
+     * Returns the list of enabled arguments.
+     * @return the list of enabled arguments
+     */
+    @API(since = "5.6", status = API.Status.EXPERIMENTAL)
+    public Iterable<JMeterProperty> getEnabledArguments() {
+        return () -> new FilterIterator<>(iterator(), property -> {
+            Object value = property.getObjectValue();
+            return value instanceof Argument && ((Argument) value).isEnabled();
+        });
+    }
+
     /**
      * Create a string representation of the arguments.
      *

src/core/src/main/java/org/apache/jmeter/engine/StandardJMeterEngine.java

@@ -185,13 +185,13 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
     @Override
     public void configure(HashTree testTree) {
         // Is testplan serialised?
-        SearchByClass<TestPlan> testPlan = new SearchByClass<>(TestPlan.class);
+        var testPlan = new SearchByClass<>(TestPlan.class);
         testTree.traverse(testPlan);
-        Object[] plan = testPlan.getSearchResults().toArray();
+        var plan = testPlan.getSearchResults().toArray();
         if (plan.length == 0) {
             throw new IllegalStateException("Could not find the TestPlan class!");
         }
-        TestPlan tp = (TestPlan) plan[0];
+        var tp = (TestPlan) plan[0];
         serialized = tp.isSerialized();
         tearDownOnShutdown = tp.isTearDownOnShutdown();
         active = true;
@@ -409,7 +409,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
 
         JMeterContextService.startTest();
         try {
-            PreCompiler compiler = new PreCompiler();
+            var compiler = new PreCompiler();
             test.traverse(compiler);
         } catch (RuntimeException e) {
             log.error("Error occurred compiling the tree:",e);
@@ -420,7 +420,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
          * Notification of test listeners needs to happen after function
          * replacement, but before setting RunningVersion to true.
          */
-        SearchByClass<TestStateListener> testListeners = new SearchByClass<>(TestStateListener.class); // TL - S&E
+        var testListeners = new SearchByClass<>(TestStateListener.class); // TL - S&E
         test.traverse(testListeners);
 
         // Merge in any additional test listeners
@@ -431,12 +431,12 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
         test.traverse(new TurnElementsOn());
         notifyTestListenersOfStart(testListeners);
 
-        List<?> testLevelElements = new ArrayList<>(test.list(test.getArray()[0]));
+        var testLevelElements = new ArrayList<>(test.list(test.getArray()[0]));
         removeThreadGroups(testLevelElements);
 
-        SearchByClass<SetupThreadGroup> setupSearcher = new SearchByClass<>(SetupThreadGroup.class);
-        SearchByClass<AbstractThreadGroup> searcher = new SearchByClass<>(AbstractThreadGroup.class);
-        SearchByClass<PostThreadGroup> postSearcher = new SearchByClass<>(PostThreadGroup.class);
+        var setupSearcher = new SearchByClass<>(SetupThreadGroup.class);
+        var searcher = new SearchByClass<>(AbstractThreadGroup.class);
+        var postSearcher = new SearchByClass<>(PostThreadGroup.class);
 
         test.traverse(setupSearcher);
         test.traverse(searcher);
@@ -446,11 +446,11 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
         // for each thread group, generate threads
         // hand each thread the sampler controller
         // and the listeners, and the timer
-        Iterator<SetupThreadGroup> setupIter = setupSearcher.getSearchResults().iterator();
-        Iterator<AbstractThreadGroup> iter = searcher.getSearchResults().iterator();
-        Iterator<PostThreadGroup> postIter = postSearcher.getSearchResults().iterator();
+        var setupIter = setupSearcher.getSearchResults().iterator();
+        var iter = searcher.getSearchResults().iterator();
+        var postIter = postSearcher.getSearchResults().iterator();
 
-        ListenerNotifier notifier = new ListenerNotifier();
+        var notifier = new ListenerNotifier();
 
         int groupCount = 0;
         JMeterContextService.clearTotalThreads();
@@ -458,9 +458,9 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
         if (setupIter.hasNext()) {
             log.info("Starting setUp thread groups");
             while (running && setupIter.hasNext()) {//for each setup thread group
-                AbstractThreadGroup group = setupIter.next();
+                var group = setupIter.next();
                 groupCount++;
-                String groupName = group.getName();
+                var groupName = group.getName();
                 log.info("Starting setUp ThreadGroup: {} : {} ", groupCount, groupName);
                 startThreadGroup(group, groupCount, setupSearcher, testLevelElements, notifier);
                 if (serialized && setupIter.hasNext()) {
@@ -489,7 +489,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
         JMeterContextService.getContext().setSamplingStarted(true);
         boolean mainGroups = running; // still running at this point, i.e. setUp was not cancelled
         while (running && iter.hasNext()) {// for each thread group
-            AbstractThreadGroup group = iter.next();
+            var group = iter.next();
             //ignore Setup and Post here.  We could have filtered the searcher. but then
             //future Thread Group objects wouldn't execute.
             if (group instanceof SetupThreadGroup ||
@@ -497,7 +497,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
                 continue;
             }
             groupCount++;
-            String groupName = group.getName();
+            var groupName = group.getName();
             log.info("Starting ThreadGroup: {} : {}", groupCount, groupName);
             startThreadGroup(group, groupCount, searcher, testLevelElements, notifier);
             if (serialized && iter.hasNext()) {
@@ -527,9 +527,9 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
                 running = tearDownOnShutdown; // re-enable for tearDown if necessary
             }
             while (running && postIter.hasNext()) {//for each setup thread group
-                AbstractThreadGroup group = postIter.next();
+                var group = postIter.next();
                 groupCount++;
-                String groupName = group.getName();
+                var groupName = group.getName();
                 log.info("Starting tearDown ThreadGroup: {} : {}", groupCount, groupName);
                 startThreadGroup(group, groupCount, postSearcher, testLevelElements, notifier);
                 if (serialized && postIter.hasNext()) {
@@ -557,7 +557,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
             boolean onErrorStopTestNow = group.getOnErrorStopTestNow();
             boolean onErrorStopThread = group.getOnErrorStopThread();
             boolean onErrorStartNextLoop = group.getOnErrorStartNextLoop();
-            String groupName = group.getName();
+            var groupName = group.getName();
             log.info("Starting {} threads for group {}.", numThreads, groupName);
             if (onErrorStopTest) {
                 log.info("Test will stop on error");
@@ -570,7 +570,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
             } else {
                 log.info("Thread will continue on error");
             }
-            ListedHashTree threadGroupTree = (ListedHashTree) searcher.getSubTree(group);
+            var threadGroupTree = (ListedHashTree) searcher.getSubTree(group);
             threadGroupTree.add(group, testLevelElements);
 
             groups.add(group);

src/core/src/main/java/org/apache/jmeter/gui/GuiPackage.java

@@ -432,13 +432,12 @@ public final class GuiPackage implements LocaleChangeListener, HistoryListener {
     }
 
     private void updateUi(JMeterGUIComponent comp) {
-        if (!(comp instanceof JComponent)) {
+        if (!(comp instanceof JComponent jc)) {
             return;
         }
-        JComponent jc = (JComponent) comp;
         Object epoch = jc.getClientProperty(LAF_EPOCH);
         int currentLafEpoch = lafEpoch.get();
-        if (epoch instanceof Integer && ((Integer) epoch) < currentLafEpoch) {
+        if (epoch instanceof Integer epochInt && epochInt < currentLafEpoch) {
             JFactory.updateUi(jc);
         }
         jc.putClientProperty(LAF_EPOCH, currentLafEpoch);

src/core/src/main/java/org/apache/jmeter/save/CSVSaveService.java

@@ -228,10 +228,10 @@ public final class CSVSaveService {
                                 Arrays.asList(DATE_FORMAT_STRINGS));
                         boolean foundMatch = false;
                         for(String fmt : DATE_FORMAT_STRINGS) {
-                            SimpleDateFormat dateFormat = new SimpleDateFormat(fmt);
+                            var dateFormat = new SimpleDateFormat(fmt);
                             dateFormat.setLenient(false);
                             try {
-                                Date stamp = dateFormat.parse(text);
+                                var stamp = dateFormat.parse(text);
                                 timeStamp = stamp.getTime();
                                 log.warn("Setting date format to: {}", fmt);
                                 saveConfig.setDateFormat(fmt);
@@ -246,7 +246,7 @@ public final class CSVSaveService {
                         }
                     }
                 } else if (saveConfig.strictDateFormatter() != null) {
-                    Date stamp = saveConfig.strictDateFormatter().parse(text);
+                    var stamp = saveConfig.strictDateFormatter().parse(text);
                     timeStamp = stamp.getTime();
                 } else { // can this happen?
                     final String msg = "Unknown timestamp format";

src/core/src/main/java/org/apache/jmeter/save/converters/SampleSaveConfigurationConverter.java

@@ -84,23 +84,14 @@ public class SampleSaveConfigurationConverter  extends ReflectionConverter {
             }
             // These are new fields; not saved unless true
             // This list MUST agree with the list in the marshall() method below
-            switch (fieldName) {
-                case NODE_BYTES:
-                case NODE_SENT_BYTES:
-                case NODE_URL:
-                case NODE_FILENAME:
-                case NODE_HOSTNAME:
-                case NODE_THREAD_COUNT:
-                case NODE_SAMPLE_COUNT:
-                case NODE_IDLE_TIME:
-                case NODE_CONNECT_TIME:
-                // The two fields below are not currently saved or restored
-                case NODE_DELIMITER:
-                case NODE_PRINTMS:
-                    return false;
-                default:
-                    return true;
-            }
+            return switch (fieldName) {
+                case NODE_BYTES, NODE_SENT_BYTES, NODE_URL, NODE_FILENAME,
+                     NODE_HOSTNAME, NODE_THREAD_COUNT, NODE_SAMPLE_COUNT,
+                     NODE_IDLE_TIME, NODE_CONNECT_TIME,
+                     // The two fields below are not currently saved or restored
+                     NODE_DELIMITER, NODE_PRINTMS -> false;
+                default -> true;
+            };
         }
     }
 

src/core/src/main/java/org/apache/jmeter/testbeans/TestBeanHelper.java

@@ -174,18 +174,18 @@ public class TestBeanHelper {
 
     private static Object unwrapProperty(PropertyDescriptor desc, JMeterProperty jprop, Class<?> type) {
         Object value;
-        if(jprop instanceof TestElementProperty)
+        if(jprop instanceof TestElementProperty testElementProperty)
         {
-            TestElement te = ((TestElementProperty)jprop).getElement();
+            TestElement te = testElementProperty.getElement();
             if(te instanceof TestBean)
             {
                 prepare(te);
             }
             value = te;
         }
-        else if(jprop instanceof MultiProperty)
+        else if(jprop instanceof MultiProperty multiProperty)
         {
-            value = unwrapCollection((MultiProperty)jprop,(String)desc.getValue(TableEditor.CLASSNAME));
+            value = unwrapCollection(multiProperty,(String)desc.getValue(TableEditor.CLASSNAME));
         }
         // value was not provided, and this is allowed
         else if (jprop instanceof NullProperty &&
@@ -200,10 +200,10 @@ public class TestBeanHelper {
 
     private static Object unwrapCollection(MultiProperty prop, String type)
     {
-        if(prop instanceof CollectionProperty)
+        if(prop instanceof CollectionProperty collectionProperty)
         {
             Collection<Object> values = new ArrayList<>();
-            for (JMeterProperty jMeterProperty : prop) {
+            for (JMeterProperty jMeterProperty : collectionProperty) {
                 try {
                     values.add(unwrapProperty(null, jMeterProperty, Class.forName(type)));
                 }

src/core/src/main/java/org/apache/jmeter/testelement/AbstractTestElement.java

@@ -236,9 +236,9 @@ public abstract class AbstractTestElement implements TestElement, Serializable,
      */
     @Override
     public boolean equals(Object o) {
-        if (o instanceof AbstractTestElement) {
+        if (o instanceof AbstractTestElement other) {
             try (ResourceLock ignored = readLock()) {
-                return ((AbstractTestElement) o).propMap.equals(propMap);
+                return other.propMap.equals(propMap);
             }
         } else {
             return false;

src/core/src/main/java/org/apache/jmeter/testelement/property/AbstractProperty.java

@@ -195,13 +195,12 @@ public abstract class AbstractProperty implements JMeterProperty {
      */
     @Override
     public boolean equals(Object o) {
-        if (!(o instanceof JMeterProperty)) {
+        if (!(o instanceof JMeterProperty jpo)) {
             return false;
         }
         if (this == o) {
             return true;
         }
-        JMeterProperty jpo = (JMeterProperty) o;
         if (!name.equals(jpo.getName())) {
             return false;
         }
@@ -275,18 +274,18 @@ public abstract class AbstractProperty implements JMeterProperty {
         if (item == null) {
             return new NullProperty();
         }
-        if (item instanceof String) {
-            return new StringProperty("", item.toString());
-        } else if (item instanceof Boolean) {
-            return new BooleanProperty("", (Boolean) item);
-        } else if (item instanceof Float) {
-            return new FloatProperty("", (Float) item);
-        } else if (item instanceof Double) {
-            return new DoubleProperty("", (Double) item);
-        } else if (item instanceof Integer) {
-            return new IntegerProperty("", (Integer) item);
-        } else if (item instanceof Long) {
-            return new LongProperty("", (Long) item);
+        if (item instanceof String str) {
+            return new StringProperty("", str);
+        } else if (item instanceof Boolean bool) {
+            return new BooleanProperty("", bool);
+        } else if (item instanceof Float floatVal) {
+            return new FloatProperty("", floatVal);
+        } else if (item instanceof Double doubleVal) {
+            return new DoubleProperty("", doubleVal);
+        } else if (item instanceof Integer intVal) {
+            return new IntegerProperty("", intVal);
+        } else if (item instanceof Long longVal) {
+            return new LongProperty("", longVal);
         } else {
             return new StringProperty("", item.toString());
         }
@@ -341,8 +340,8 @@ public abstract class AbstractProperty implements JMeterProperty {
                 Object key = entry.getKey();
                 Object prop = entry.getValue();
                 String item=null;
-                if (key instanceof String) {
-                    item = (String) key;
+                if (key instanceof String keyStr) {
+                    item = keyStr;
                 } else {
                     if (key != null) {
                         log.error("Expected key type String, found: {}", key.getClass());
@@ -378,18 +377,17 @@ public abstract class AbstractProperty implements JMeterProperty {
      * @return the JMeterProperty
      */
     protected static JMeterProperty makeProperty(Object item) {
-        if (item instanceof JMeterProperty) {
-            return (JMeterProperty) item;
+        if (item instanceof JMeterProperty prop) {
+            return prop;
         }
-        if (item instanceof TestElement) {
-            return new TestElementProperty(((TestElement) item).getName(),
-                    (TestElement) item);
+        if (item instanceof TestElement testElement) {
+            return new TestElementProperty(testElement.getName(), testElement);
         }
-        if (item instanceof Collection<?>) {
-            return new CollectionProperty(Integer.toString(item.hashCode()), (Collection<?>) item);
+        if (item instanceof Collection<?> collection) {
+            return new CollectionProperty(Integer.toString(item.hashCode()), collection);
         }
-        if (item instanceof Map<?, ?>) {
-            return new MapProperty(Integer.toString(item.hashCode()), (Map<?, ?>) item);
+        if (item instanceof Map<?, ?> map) {
+            return new MapProperty(Integer.toString(item.hashCode()), map);
         }
         return null;
     }

src/core/src/main/java/org/apache/jmeter/testelement/property/CollectionProperty.java

@@ -66,27 +66,27 @@ public class CollectionProperty extends MultiProperty {
     }
 
     public void set(int index, String prop) {
-        if (value instanceof List<?>) {
-            ((List<JMeterProperty>) value).set(index, new StringProperty(prop, prop));
+        if (value instanceof List<JMeterProperty> list) {
+            list.set(index, new StringProperty(prop, prop));
         }
     }
 
     public void set(int index, JMeterProperty prop) {
-        if (value instanceof List<?>) {
-            ((List<JMeterProperty>) value).set(index, prop);
+        if (value instanceof List<JMeterProperty> list) {
+            list.set(index, prop);
         }
     }
 
     public JMeterProperty get(int row) {
-        if (value instanceof List<?>) {
-            return ((List<JMeterProperty>) value).get(row);
+        if (value instanceof List<JMeterProperty> list) {
+            return list.get(row);
         }
         return null;
     }
 
     public void remove(int index) {
-        if (value instanceof List<?>) {
-            ((List<?>) value).remove(index);
+        if (value instanceof List<?> list) {
+            list.remove(index);
         }
     }
 

src/core/src/main/java/org/apache/jmeter/threads/JMeterThread.java

@@ -355,8 +355,8 @@ public class JMeterThread implements Runnable, Interruptible {
     private void triggerLoopLogicalActionOnParentControllers(Sampler sampler, JMeterContext threadContext,
             Consumer<? super FindTestElementsUpToRootTraverser> consumer) {
         TransactionSampler transactionSampler = null;
-        if (sampler instanceof TransactionSampler) {
-            transactionSampler = (TransactionSampler) sampler;
+        if (sampler instanceof TransactionSampler transSampler) {
+            transactionSampler = transSampler;
         }
 
         Sampler realSampler = findRealSampler(sampler);
@@ -389,11 +389,10 @@ public class JMeterThread implements Runnable, Interruptible {
     private static void continueOnCurrentLoop(FindTestElementsUpToRootTraverser pathToRootTraverser) {
         List<Controller> controllersToReinit = pathToRootTraverser.getControllersToRoot();
         for (Controller parentController : controllersToReinit) {
-            if (parentController instanceof AbstractThreadGroup) {
-                AbstractThreadGroup tg = (AbstractThreadGroup) parentController;
+            if (parentController instanceof AbstractThreadGroup tg) {
                 tg.startNextLoop();
-            } else if (parentController instanceof IteratingController) {
-                ((IteratingController) parentController).startNextLoop();
+            } else if (parentController instanceof IteratingController iterController) {
+                iterController.startNextLoop();
                 break;
             } else {
                 parentController.triggerEndOfLoop();
@@ -409,11 +408,10 @@ public class JMeterThread implements Runnable, Interruptible {
     private static void breakOnCurrentLoop(FindTestElementsUpToRootTraverser pathToRootTraverser) {
         List<Controller> controllersToReinit = pathToRootTraverser.getControllersToRoot();
         for (Controller parentController : controllersToReinit) {
-            if (parentController instanceof AbstractThreadGroup) {
-                AbstractThreadGroup tg = (AbstractThreadGroup) parentController;
+            if (parentController instanceof AbstractThreadGroup tg) {
                 tg.breakThreadLoop();
-            } else if (parentController instanceof IteratingController) {
-                ((IteratingController) parentController).breakLoop();
+            } else if (parentController instanceof IteratingController iterController) {
+                iterController.breakLoop();
                 break;
             } else {
                 parentController.triggerEndOfLoop();
@@ -448,8 +446,8 @@ public class JMeterThread implements Runnable, Interruptible {
      */
     private static Sampler findRealSampler(Sampler sampler) {
         Sampler realSampler = sampler;
-        while (realSampler instanceof TransactionSampler) {
-            realSampler = ((TransactionSampler) realSampler).getSubSampler();
+        while (realSampler instanceof TransactionSampler transSampler) {
+            realSampler = transSampler.getSubSampler();
         }
         return realSampler;
     }
@@ -469,8 +467,8 @@ public class JMeterThread implements Runnable, Interruptible {
         // Find the package for the transaction
         SamplePackage transactionPack = null;
         try {
-            if (current instanceof TransactionSampler) {
-                transactionSampler = (TransactionSampler) current;
+            if (current instanceof TransactionSampler transSampler) {
+                transactionSampler = transSampler;
                 transactionPack = compiler.configureTransactionSampler(transactionSampler);
 
                 // Check if the transaction is done
@@ -641,8 +639,8 @@ public class JMeterThread implements Runnable, Interruptible {
         currentSamplerForInterruption = sampler;
         if (!sampleMonitors.isEmpty()) {
             for (SampleMonitor sampleMonitor : sampleMonitors) {
-                if(sampleMonitor instanceof TestElement) {
-                    TestBeanHelper.prepare((TestElement) sampleMonitor);
+                if(sampleMonitor instanceof TestElement testElement) {
+                    TestBeanHelper.prepare(testElement);
                 }
                 sampleMonitor.sampleStarting(sampler);
             }
@@ -795,8 +793,7 @@ public class JMeterThread implements Runnable, Interruptible {
 
         @Override
         public void addNode(Object node, HashTree subTree) {
-            if (node instanceof ThreadListener) {
-                ThreadListener tl = (ThreadListener) node;
+            if (node instanceof ThreadListener tl) {
                 if (isStart) {
                     try {
                         tl.threadStarted();
@@ -902,8 +899,7 @@ public class JMeterThread implements Runnable, Interruptible {
     private static void checkAssertions(List<? extends Assertion> assertions, SampleResult parent, JMeterContext threadContext) {
         for (Assertion assertion : assertions) {
             TestBeanHelper.prepare((TestElement) assertion);
-            if (assertion instanceof AbstractScopedAssertion) {
-                AbstractScopedAssertion scopedAssertion = (AbstractScopedAssertion) assertion;
+            if (assertion instanceof AbstractScopedAssertion scopedAssertion) {
                 String scope = scopedAssertion.fetchScope();
                 if (scopedAssertion.isScopeParent(scope)
                         || scopedAssertion.isScopeAll(scope)
@@ -1031,8 +1027,8 @@ public class JMeterThread implements Runnable, Interruptible {
         threadVars.incIteration();
         for (TestIterationListener listener : testIterationStartListeners) {
             listener.testIterationStart(new LoopIterationEvent(threadGroupLoopController, threadVars.getIteration()));
-            if (listener instanceof TestElement) {
-                ((TestElement) listener).recoverRunningVersion();
+            if (listener instanceof TestElement testElement) {
+                testElement.recoverRunningVersion();
             }
         }
     }

src/core/src/main/java/org/apache/jmeter/threads/TestCompiler.java

@@ -136,11 +136,11 @@ public class TestCompiler implements HashTreeTraverser {
         }
         TestElement child = stack.getLast();
         trackIterationListeners(stack);
-        if (child instanceof Sampler) {
-            saveSamplerConfigs((Sampler) child);
+        if (child instanceof Sampler sampler) {
+            saveSamplerConfigs(sampler);
         }
-        else if(child instanceof TransactionController) {
-            saveTransactionControllerConfigs((TransactionController) child);
+        else if(child instanceof TransactionController transactionController) {
+            saveTransactionControllerConfigs(transactionController);
         }
         stack.removeLast();
         if (!stack.isEmpty()) {
@@ -148,8 +148,7 @@ public class TestCompiler implements HashTreeTraverser {
             boolean duplicate = false;
             // Bug 53750: this condition used to be in ObjectPair#addTestElements()
             if (parent instanceof Controller && (child instanceof Sampler || child instanceof Controller)) {
-                if (parent instanceof TestCompilerHelper) {
-                    TestCompilerHelper te = (TestCompilerHelper) parent;
+                if (parent instanceof TestCompilerHelper te) {
                     duplicate = !te.addTestElementOnce(child);
                 } else { // this is only possible for 3rd party controllers by default
                     ObjectPair pair = new ObjectPair(child, parent);
@@ -174,16 +173,16 @@ public class TestCompiler implements HashTreeTraverser {
     @SuppressWarnings("NonApiType")
     private static void trackIterationListeners(LinkedList<TestElement> pStack) {
         TestElement child = pStack.getLast();
-        if (child instanceof LoopIterationListener) {
+        if (child instanceof LoopIterationListener loopListener) {
             ListIterator<TestElement> iter = pStack.listIterator(pStack.size());
             while (iter.hasPrevious()) {
                 TestElement item = iter.previous();
                 if (item == child) {
                     continue;
                 }
-                if (item instanceof Controller) {
+                if (item instanceof Controller controller) {
                     TestBeanHelper.prepare(child);
-                    ((Controller) item).addIterationListener((LoopIterationListener) child);
+                    controller.addIterationListener(loopListener);
                     break;
                 }
             }
@@ -209,23 +208,23 @@ public class TestCompiler implements HashTreeTraverser {
             List<PostProcessor> tempPost = new ArrayList<>();
             List<Assertion> tempAssertions = new ArrayList<>();
             for (Object item : testTree.list(stack.subList(0, i))) {
-                if (item instanceof ConfigTestElement) {
-                    configs.add((ConfigTestElement) item);
+                if (item instanceof ConfigTestElement configElement) {
+                    configs.add(configElement);
                 }
-                if (item instanceof SampleListener) {
-                    listeners.add((SampleListener) item);
+                if (item instanceof SampleListener listener) {
+                    listeners.add(listener);
                 }
-                if (item instanceof Timer) {
-                    timers.add((Timer) item);
+                if (item instanceof Timer timer) {
+                    timers.add(timer);
                 }
-                if (item instanceof Assertion) {
-                    tempAssertions.add((Assertion) item);
+                if (item instanceof Assertion assertion) {
+                    tempAssertions.add(assertion);
                 }
-                if (item instanceof PostProcessor) {
-                    tempPost.add((PostProcessor) item);
+                if (item instanceof PostProcessor postProcessor) {
+                    tempPost.add(postProcessor);
                 }
-                if (item instanceof PreProcessor) {
-                    tempPre.add((PreProcessor) item);
+                if (item instanceof PreProcessor preProcessor) {
+                    tempPre.add(preProcessor);
                 }
             }
             assertions.addAll(0, tempAssertions);
@@ -251,11 +250,11 @@ public class TestCompiler implements HashTreeTraverser {
         for (int i = stack.size(); i > 0; i--) {
             addDirectParentControllers(controllers, stack.get(i - 1));
             for (Object item : testTree.list(stack.subList(0, i))) {
-                if (item instanceof SampleListener) {
-                    listeners.add((SampleListener) item);
+                if (item instanceof SampleListener listener) {
+                    listeners.add(listener);
                 }
-                if (item instanceof Assertion) {
-                    assertions.add((Assertion) item);
+                if (item instanceof Assertion assertion) {
+                    assertions.add(assertion);
                 }
             }
         }
@@ -272,9 +271,9 @@ public class TestCompiler implements HashTreeTraverser {
      * @param maybeController
      */
     private static void addDirectParentControllers(List<? super Controller> controllers, TestElement maybeController) {
-        if (maybeController instanceof Controller) {
+        if (maybeController instanceof Controller controller) {
             log.debug("adding controller: {} to sampler config", maybeController);
-            controllers.add((Controller) maybeController);
+            controllers.add(controller);
         }
     }
 
@@ -297,8 +296,8 @@ public class TestCompiler implements HashTreeTraverser {
         /** {@inheritDoc} */
         @Override
         public boolean equals(Object o) {
-            if (o instanceof ObjectPair) {
-                return child == ((ObjectPair) o).child && parent == ((ObjectPair) o).parent;
+            if (o instanceof ObjectPair other) {
+                return child == other.child && parent == other.parent;
             }
             return false;
         }
@@ -309,8 +308,8 @@ public class TestCompiler implements HashTreeTraverser {
         for (ConfigTestElement config  : configs) {
             if (!(config instanceof NoConfigMerge))
             {
-                if(sam instanceof ConfigMergabilityIndicator) {
-                    if(((ConfigMergabilityIndicator)sam).applies(config)) {
+                if(sam instanceof ConfigMergabilityIndicator indicator) {
+                    if(indicator.applies(config)) {
                         sam.addTestElement(config);
                     }
                 } else {

src/functions/src/main/java/org/apache/jmeter/functions/ChangeCase.java

@@ -80,25 +80,18 @@ public class ChangeCase extends AbstractFunction {
     }
 
     protected String changeCase(String originalString, String mode) {
-        String targetString = originalString;
         // mode is case insensitive, allow upper for example
         ChangeCaseMode changeCaseMode = ChangeCaseMode.typeOf(mode.toUpperCase(Locale.ROOT));
-        if (changeCaseMode != null) {
-            switch (changeCaseMode) {
-            case UPPER:
-                targetString = StringUtils.upperCase(originalString);
-                break;
-            case LOWER:
-                targetString = StringUtils.lowerCase(originalString);
-                break;
-            case CAPITALIZE:
-                targetString = StringUtils.capitalize(originalString);
-                break;
-            }
-        } else {
-            LOGGER.error("Unknown mode {}, returning {} unchanged", mode, targetString);
+        if (changeCaseMode == null) {
+            LOGGER.error("Unknown mode {}, returning {} unchanged", mode, originalString);
+            return originalString;
         }
-        return targetString;
+        
+        return switch (changeCaseMode) {
+            case UPPER -> StringUtils.upperCase(originalString);
+            case LOWER -> StringUtils.lowerCase(originalString);
+            case CAPITALIZE -> StringUtils.capitalize(originalString);
+        };
     }
 
     @Override

src/functions/src/main/java/org/apache/jmeter/functions/CharFunction.java

@@ -57,9 +57,9 @@ public class CharFunction extends AbstractFunction {
     public String execute(SampleResult previousResult, Sampler currentSampler)
             throws InvalidVariableException {
 
-        StringBuilder sb = new StringBuilder(values.length);
+        var sb = new StringBuilder(values.length);
         for (Object val : values) {
-            String numberString = ((CompoundVariable) val).execute().trim();
+            var numberString = ((CompoundVariable) val).execute().trim();
             try {
                 long value = Long.decode(numberString);
                 char ch = (char) value;

src/functions/src/main/java/org/apache/jmeter/functions/LogFunction.java

@@ -164,21 +164,11 @@ public class LogFunction extends AbstractFunction {
             final String separator = comment.isEmpty() ? DEFAULT_SEPARATOR : comment;
 
             switch (prioLevel) {
-                case ERROR:
-                    logger.error("{} {} {}", threadName, separator, stringToLog, throwable);
-                    break;
-                case WARN:
-                    logger.warn("{} {} {}", threadName, separator, stringToLog, throwable);
-                    break;
-                case INFO:
-                    logger.info("{} {} {}", threadName, separator, stringToLog, throwable);
-                    break;
-                case DEBUG:
-                    logger.debug("{} {} {}", threadName, separator, stringToLog, throwable);
-                    break;
-                case TRACE:
-                    logger.trace("{} {} {}", threadName, separator, stringToLog, throwable);
-                    break;
+                case ERROR -> logger.error("{} {} {}", threadName, separator, stringToLog, throwable);
+                case WARN -> logger.warn("{} {} {}", threadName, separator, stringToLog, throwable);
+                case INFO -> logger.info("{} {} {}", threadName, separator, stringToLog, throwable);
+                case DEBUG -> logger.debug("{} {} {}", threadName, separator, stringToLog, throwable);
+                case TRACE -> logger.trace("{} {} {}", threadName, separator, stringToLog, throwable);
             }
         }
     }

src/functions/src/main/java/org/apache/jmeter/functions/RegexFunction.java

@@ -182,8 +182,8 @@ public class RegexFunction extends AbstractFunction {
         }
 
         if (valueIndex.equals(ALL)) {
-            StringBuilder value = new StringBuilder();
-            Iterator<java.util.regex.MatchResult> it = collectAllMatches.iterator();
+            var value = new StringBuilder();
+            var it = collectAllMatches.iterator();
             boolean first = true;
             while (it.hasNext()) {
                 if (!first) {
@@ -195,7 +195,7 @@ public class RegexFunction extends AbstractFunction {
             }
             return value.toString();
         } else if (valueIndex.equals(RAND)) {
-            java.util.regex.MatchResult result = collectAllMatches.get(
+            var result = collectAllMatches.get(
                     ThreadLocalRandom.current().nextInt(collectAllMatches.size()));
             return generateResult(result, name, tmplt, vars);
         } else {
@@ -313,7 +313,7 @@ public class RegexFunction extends AbstractFunction {
 
     private static String generateResult(MatchResult match, String namep, Object[] template, JMeterVariables vars) {
         saveGroups(match, namep, vars);
-        StringBuilder result = new StringBuilder();
+        var result = new StringBuilder();
         for (Object t : template) {
             if (t instanceof String) {
                 result.append(t);

src/functions/src/main/java/org/apache/jmeter/functions/StringFromFile.java

@@ -296,7 +296,7 @@ public class StringFromFile extends AbstractFunction implements TestStateListene
         checkParameterCount(parameters, MIN_PARAM_COUNT, MAX_PARAM_COUNT);
         values = parameters.toArray();
 
-        StringBuilder sb = new StringBuilder(40);
+        var sb = new StringBuilder(40);
         sb.append("setParameters(");//$NON-NLS-1$
         for (int i = 0; i < values.length; i++) {
             if (i > 0) {

src/jorphan/src/main/java/org/apache/jorphan/collections/HashTree.java

@@ -95,8 +95,10 @@ public class HashTree implements Serializable, Map<Object, HashTree>, Cloneable
      */
     private HashTree(Map<Object, ? extends HashTree> _map, Object key) {
         if(_map != null) {
-            if (_map instanceof IdentityHashMap) {
-                data = (IdentityHashMap<Object, HashTree>) _map;
+            if (_map instanceof IdentityHashMap<?, ?> identityMapRaw) {
+                @SuppressWarnings("unchecked")
+                IdentityHashMap<Object, HashTree> identityMap = (IdentityHashMap<Object, HashTree>) identityMapRaw;
+                data = identityMap;
             } else {
                 // Technically speaking, TestElements can't be placed in HashMapk keys,
                 // so we have to convert the map to an IdentityHashMap.
@@ -122,8 +124,8 @@ public class HashTree implements Serializable, Map<Object, HashTree>, Cloneable
      */
     @Override
     public void putAll(Map<?, ? extends HashTree> map) {
-        if (map instanceof HashTree) {
-            this.add((HashTree) map);
+        if (map instanceof HashTree hashTree) {
+            this.add(hashTree);
         } else {
             throw new UnsupportedOperationException("can only putAll other HashTree objects");
         }
@@ -916,7 +918,7 @@ public class HashTree implements Serializable, Map<Object, HashTree>, Cloneable
         if (o == this) {
             return true;
         }
-        if (!(o instanceof HashTree)) {
+        if (!(o instanceof HashTree hashTree)) {
             return false;
         }
         HashTree oo = (HashTree) o;

src/jorphan/src/main/java/org/apache/jorphan/util/Converter.java

@@ -90,8 +90,8 @@ public class Converter {
      */
     public static Calendar getCalendar(Object date, Calendar defaultValue) {
         Calendar cal = new GregorianCalendar();
-        if (date instanceof java.util.Date) {
-            cal.setTime((java.util.Date) date);
+        if (date instanceof java.util.Date dateValue) {
+            cal.setTime(dateValue);
             return cal;
         } else if (date != null) {
             Optional<Date> d = tryToParseDate(date);
@@ -145,8 +145,8 @@ public class Converter {
      *         <code>defaultValue</code> if conversion failed
      */
     public static Date getDate(Object date, Date defaultValue) {
-        if (date instanceof java.util.Date) {
-            return (Date) date;
+        if (date instanceof java.util.Date dateValue) {
+            return dateValue;
         } else if (date != null) {
             return tryToParseDate(date).orElse(defaultValue);
         } else {
@@ -182,8 +182,8 @@ public class Converter {
         if (o == null) {
             return defaultValue;
         }
-        if (o instanceof Number) {
-            return ((Number) o).floatValue();
+        if (o instanceof Number number) {
+            return number.floatValue();
         }
         try {
             return Float.parseFloat(o.toString());
@@ -221,8 +221,8 @@ public class Converter {
             if (o == null) {
                 return defaultValue;
             }
-            if (o instanceof Number) {
-                return ((Number) o).doubleValue();
+            if (o instanceof Number number) {
+                return number.doubleValue();
             }
             return Double.parseDouble(o.toString());
         } catch (NumberFormatException e) {
@@ -270,8 +270,8 @@ public class Converter {
     public static boolean getBoolean(Object o, boolean defaultValue) {
         if (o == null) {
             return defaultValue;
-        } else if (o instanceof Boolean) {
-            return (Boolean) o;
+        } else if (o instanceof Boolean boolValue) {
+            return boolValue;
         }
         return Boolean.parseBoolean(o.toString());
     }
@@ -291,8 +291,8 @@ public class Converter {
             if (o == null) {
                 return defaultValue;
             }
-            if (o instanceof Number) {
-                return ((Number) o).intValue();
+            if (o instanceof Number number) {
+                return number.intValue();
             }
             return Integer.parseInt(o.toString());
         } catch (NumberFormatException e) {
@@ -327,12 +327,12 @@ public class Converter {
             if (o == null) {
                 return defaultValue;
             }
-            if (o instanceof Character) {
-                return (Character) o;
-            } else if (o instanceof Byte) {
-                return (char) ((Byte) o).byteValue();
-            } else if (o instanceof Integer) {
-                return (char) ((Integer) o).intValue();
+            if (o instanceof Character charValue) {
+                return charValue;
+            } else if (o instanceof Byte byteValue) {
+                return (char) byteValue.byteValue();
+            } else if (o instanceof Integer intValue) {
+                return (char) intValue.intValue();
             } else {
                 String s = o.toString();
                 if (s.length() > 0) {
@@ -373,8 +373,8 @@ public class Converter {
             if (o == null) {
                 return defaultValue;
             }
-            if (o instanceof Number) {
-                return ((Number) o).longValue();
+            if (o instanceof Number number) {
+                return number.longValue();
             }
             return Long.parseLong(o.toString());
         } catch (NumberFormatException e) {
@@ -546,11 +546,11 @@ public class Converter {
      *             when object can not be converted
      */
     public static File getFile(Object o){
-        if (o instanceof File) {
-            return (File) o;
+        if (o instanceof File file) {
+            return file;
         }
-        if (o instanceof String) {
-            return new File((String) o);
+        if (o instanceof String str) {
+            return new File(str);
         }
         throw new IllegalArgumentException("Expected String or file, actual "+o.getClass().getName());
     }

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/config/gui/UrlConfigGui.java

@@ -261,7 +261,7 @@ public class UrlConfigGui extends JPanel implements ChangeListener {
      */
     private static String computePostBody(Arguments arguments, boolean crlfToLF) {
         StringBuilder postBody = new StringBuilder();
-        for (JMeterProperty argument : arguments) {
+        for (JMeterProperty argument : arguments.getEnabledArguments()) {
             HTTPArgument arg = (HTTPArgument) argument.getObjectValue();
             String value = arg.getValue();
             if (crlfToLF) {

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/control/CacheManager.java

@@ -211,8 +211,8 @@ public class CacheManager extends ConfigTestElement implements TestStateListener
         if (headerName == null) {
             return null;
         }
-        final Set<String> names = new HashSet<>(Arrays.asList(headerName.split(",\\s*")));
-        final Map<String, List<String>> values = new HashMap<>();
+        final var names = new HashSet<>(Arrays.asList(headerName.split(",\\s*")));
+        final var values = new HashMap<String, List<String>>();
         for (final String name: names) {
             values.put(name, new ArrayList<>());
         }

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/curl/BasicCurlParser.java

@@ -287,19 +287,12 @@ public class BasicCurlParser {
         public void setLimitRate(String limitRate) {
             String unit = limitRate.substring(limitRate.length() - 1, limitRate.length()).toLowerCase(Locale.ROOT);
             int value = Integer.parseInt(limitRate.substring(0, limitRate.length() - 1).toLowerCase(Locale.ROOT));
-            switch (unit) {
-            case "k":
-                this.limitRate = value * ONE_KILOBYTE_IN_CPS;
-                break;
-            case "m":
-                this.limitRate = value * ONE_KILOBYTE_IN_CPS * 1000;
-                break;
-            case "g":
-                this.limitRate = value * ONE_KILOBYTE_IN_CPS * 1000000;
-                break;
-            default:
-                break;
-            }
+            this.limitRate = switch (unit) {
+                case "k" -> value * ONE_KILOBYTE_IN_CPS;
+                case "m" -> value * ONE_KILOBYTE_IN_CPS * 1000;
+                case "g" -> value * ONE_KILOBYTE_IN_CPS * 1000000;
+                default -> this.limitRate; // Keep current value if unit is not recognized
+            };
         }
 
         /**
@@ -640,8 +633,9 @@ public class BasicCurlParser {
             "Tells curl to use HTTP negotiate authentication when communicating with the given proxy. ");
     private static final CLOptionDescriptor D_KEEPALIVETILE_OPT = new CLOptionDescriptor("keepalive-time",
             CLOptionDescriptor.ARGUMENT_REQUIRED, KEEPALIVETILE_OPT,
-            " This option sets the  time  a  connection  needs  to  remain  idle  before  sending"
-                    + " keepalive  probes and the time between individual keepalive probes..");
+            """
+                    This option sets the time a connection needs to remain idle before sending \
+                    keepalive probes and the time between individual keepalive probes..""");
     private static final CLOptionDescriptor D_MAX_TIME_OPT = new CLOptionDescriptor("max-time",
             CLOptionDescriptor.ARGUMENT_REQUIRED, MAX_TIME_OPT,
             "Maximum time in seconds that you allow the whole operation to take. ");
@@ -652,8 +646,9 @@ public class BasicCurlParser {
             "Create the necessary local directory hierarchy as needed for output file");
     private static final CLOptionDescriptor D_RAW_OPT = new CLOptionDescriptor("raw",
             CLOptionDescriptor.ARGUMENT_DISALLOWED, RAW_OPT,
-            "When used, it disables all internal HTTP decoding of content or transfer encodings "
-                    + "and instead makes them passed on unaltered raw. ");
+            """
+                    When used, it disables all internal HTTP decoding of content or transfer \
+                    encodings and instead makes them passed on unaltered raw.""");
     private static final CLOptionDescriptor D_INTERFACE_OPT = new CLOptionDescriptor("interface",
             CLOptionDescriptor.ARGUMENT_REQUIRED, INTERFACE_OPT, "Perform an operation using a specified interface");
     private static final CLOptionDescriptor D_DNS_RESOLVER_OPT = new CLOptionDescriptor("resolve",

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/gui/HTTPArgumentsPanel.java

@@ -39,12 +39,15 @@ import org.apache.jorphan.reflect.Functor;
 /**
  * A GUI panel allowing the user to enter HTTP Parameters.
  * These have names and values, as well as check-boxes to determine whether or not to
- * include the "=" sign in the output and whether or not to encode the output.
+ * include the "=" sign in the output and whether or not to encode the output and
+ * whether or not to enable them.
  */
 public class HTTPArgumentsPanel extends ArgumentsPanel {
 
     private static final long serialVersionUID = 240L;
 
+    private static final String ENABLE = "enable"; //$NON-NLS-1$
+
     private static final String ENCODE_OR_NOT = "encode?"; //$NON-NLS-1$
 
     private static final String INCLUDE_EQUALS = "include_equals"; //$NON-NLS-1$
@@ -60,21 +63,23 @@ public class HTTPArgumentsPanel extends ArgumentsPanel {
     @Override
     protected void initializeTableModel() {
         tableModel = new ObjectTableModel(new String[] {
-                ArgumentsPanel.COLUMN_RESOURCE_NAMES_0, ArgumentsPanel.COLUMN_RESOURCE_NAMES_1, ENCODE_OR_NOT, CONTENT_TYPE, INCLUDE_EQUALS },
+                ENABLE, ArgumentsPanel.COLUMN_RESOURCE_NAMES_0, ArgumentsPanel.COLUMN_RESOURCE_NAMES_1, ENCODE_OR_NOT, CONTENT_TYPE, INCLUDE_EQUALS },
                 HTTPArgument.class,
                 new Functor[] {
+                new Functor("isEnabled"), //$NON-NLS-1$
                 new Functor("getName"), //$NON-NLS-1$
                 new Functor("getValue"), //$NON-NLS-1$
                 new Functor("isAlwaysEncoded"), //$NON-NLS-1$
                 new Functor("getContentType"), //$NON-NLS-1$
                 new Functor("isUseEquals") }, //$NON-NLS-1$
                 new Functor[] {
+                new Functor("setEnabled"), //$NON-NLS-1$
                 new Functor("setName"), //$NON-NLS-1$
                 new Functor("setValue"), //$NON-NLS-1$
                 new Functor("setAlwaysEncoded"), //$NON-NLS-1$
                 new Functor("setContentType"),
                 new Functor("setUseEquals")}, //$NON-NLS-1$
-                new Class[] {String.class, String.class, Boolean.class, String.class, Boolean.class });
+                new Class[] {Boolean.class, String.class, String.class, Boolean.class, String.class, Boolean.class });
     }
 
     public static boolean testFunctors(){
@@ -85,6 +90,7 @@ public class HTTPArgumentsPanel extends ArgumentsPanel {
 
     @Override
     protected void sizeColumns(JTable table) {
+        GuiUtils.fixSize(table.getColumn(ENABLE), table);
         GuiUtils.fixSize(table.getColumn(INCLUDE_EQUALS), table);
         GuiUtils.fixSize(table.getColumn(ENCODE_OR_NOT), table);
     }

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/sampler/AjpSampler.java

@@ -279,7 +279,7 @@ public class AjpSampler extends HTTPSamplerBase implements Interruptible {
                 setString(HTTPConstants.APPLICATION_X_WWW_FORM_URLENCODED);
                 StringBuilder sb = new StringBuilder();
                 boolean first = true;
-                for (JMeterProperty arg : getArguments()) {
+                for (JMeterProperty arg : getArguments().getEnabledArguments()) {
                     if (first) {
                         first = false;
                     } else {

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/sampler/HTTPHC4Impl.java

@@ -159,7 +159,6 @@ import org.apache.jmeter.samplers.SampleResult;
 import org.apache.jmeter.services.FileServer;
 import org.apache.jmeter.testelement.property.CollectionProperty;
 import org.apache.jmeter.testelement.property.JMeterProperty;
-import org.apache.jmeter.testelement.property.PropertyIterator;
 import org.apache.jmeter.threads.JMeterContextService;
 import org.apache.jmeter.threads.JMeterVariables;
 import org.apache.jmeter.util.JMeterUtils;
@@ -1571,7 +1570,7 @@ public class HTTPHC4Impl extends HTTPHCAbstractImpl {
             }
             // Create the parts
             // Add any parameters
-            for (JMeterProperty jMeterProperty : getArguments()) {
+            for (JMeterProperty jMeterProperty : getArguments().getEnabledArguments()) {
                 HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                 String parameterName = arg.getName();
                 if (arg.isSkippable(parameterName)) {
@@ -1653,7 +1652,7 @@ public class HTTPHC4Impl extends HTTPHCAbstractImpl {
 
                     // Just append all the parameter values, and use that as the post body
                     StringBuilder postBody = new StringBuilder();
-                    for (JMeterProperty jMeterProperty : getArguments()) {
+                    for (JMeterProperty jMeterProperty : getArguments().getEnabledArguments()) {
                         HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                         postBody.append(arg.getEncodedValue(contentEncoding));
                     }
@@ -1796,10 +1795,9 @@ public class HTTPHC4Impl extends HTTPHCAbstractImpl {
     private UrlEncodedFormEntity createUrlEncodedFormEntity(final String urlContentEncoding) throws UnsupportedEncodingException {
         // It is a normal request, with parameter names and values
         // Add the parameters
-        PropertyIterator args = getArguments().iterator();
         List<NameValuePair> nvps = new ArrayList<>();
-        while (args.hasNext()) {
-            HTTPArgument arg = (HTTPArgument) args.next().getObjectValue();
+        for (JMeterProperty jMeterProperty: getArguments().getEnabledArguments()) {
+            HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
             // The HTTPClient always urlencodes both name and value,
             // so if the argument is already encoded, we have to decode
             // it before adding it to the post request

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/sampler/HTTPSamplerBase.java

@@ -81,7 +81,6 @@ import org.apache.jmeter.testelement.TestStateListener;
 import org.apache.jmeter.testelement.ThreadListener;
 import org.apache.jmeter.testelement.property.CollectionProperty;
 import org.apache.jmeter.testelement.property.JMeterProperty;
-import org.apache.jmeter.testelement.property.PropertyIterator;
 import org.apache.jmeter.testelement.schema.PropertiesAccessor;
 import org.apache.jmeter.testelement.schema.PropertyDescriptor;
 import org.apache.jmeter.threads.JMeterContext;
@@ -409,7 +408,7 @@ public abstract class HTTPSamplerBase extends AbstractSampler
             return true;
         } else {
             boolean hasArguments = false;
-            for (JMeterProperty jMeterProperty : getArguments()) {
+            for (JMeterProperty jMeterProperty : getArguments().getEnabledArguments()) {
                 hasArguments = true;
                 HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                 if (arg.getName() != null && !arg.getName().isEmpty()) {
@@ -1155,9 +1154,10 @@ public abstract class HTTPSamplerBase extends AbstractSampler
      */
     public String getQueryString(final String contentEncoding) {
 
-        CollectionProperty arguments = getArguments().getArguments();
+        Arguments args = getArguments();
+        Iterator<JMeterProperty> iter = args.getEnabledArguments().iterator();
         // Optimisation : avoid building useless objects if empty arguments
-        if(arguments.isEmpty()) {
+        if (!iter.hasNext()) {
             return "";
         }
         String lContentEncoding = contentEncoding;
@@ -1167,8 +1167,7 @@ public abstract class HTTPSamplerBase extends AbstractSampler
             lContentEncoding = EncoderCache.URL_ARGUMENT_ENCODING;
         }
 
-        StringBuilder buf = new StringBuilder(arguments.size() * 15);
-        PropertyIterator iter = arguments.iterator();
+        StringBuilder buf = new StringBuilder(args.getArgumentCount() * 15);
         boolean first = true;
         while (iter.hasNext()) {
             HTTPArgument item = null;

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/sampler/PostWriter.java

@@ -190,7 +190,7 @@ public class PostWriter {
             ByteArrayOutputStream bos = new ByteArrayOutputStream();
             OutputStreamWriter osw = new OutputStreamWriter(bos, contentEncoding);
             // Add any parameters
-            for (JMeterProperty jMeterProperty : sampler.getArguments()) {
+            for (JMeterProperty jMeterProperty : sampler.getArguments().getEnabledArguments()) {
                 HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                 String parameterName = arg.getName();
                 if (arg.isSkippable(parameterName)) {
@@ -299,7 +299,7 @@ public class PostWriter {
 
                     // Just append all the parameter values, and use that as the post body
                     StringBuilder postBodyBuffer = new StringBuilder();
-                    for (JMeterProperty jMeterProperty : sampler.getArguments()) {
+                    for (JMeterProperty jMeterProperty : sampler.getArguments().getEnabledArguments()) {
                         HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                         postBodyBuffer.append(arg.getEncodedValue(contentEncoding));
                     }

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/sampler/PutWriter.java

@@ -84,7 +84,7 @@ public class PutWriter extends PostWriter {
 
             // Just append all the parameter values, and use that as the put body
             StringBuilder putBodyBuffer = new StringBuilder();
-             for (JMeterProperty jMeterProperty : sampler.getArguments()) {
+             for (JMeterProperty jMeterProperty : sampler.getArguments().getEnabledArguments()) {
                  HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                  putBodyBuffer.append(arg.getEncodedValue(contentEncoding));
              }

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/util/ConversionUtils.java

@@ -119,20 +119,12 @@ public class ConversionUtils {
         StringBuilder sb = new StringBuilder(value.length() + 2);
         for (int i = 0; i < value.length(); i++) {
             char c = value.charAt(i);
-            switch (c) {
-                case '"':
-                    sb.append("%22");
-                    break;
-                case 0x0A:
-                    sb.append("%0A");
-                    break;
-                case 0x0D:
-                    sb.append("%0D");
-                    break;
-                default:
-                    sb.append(c);
-                    break;
-            }
+            sb.append(switch (c) {
+                case '"' -> "%22";
+                case 0x0A -> "%0A";
+                case 0x0D -> "%0D";
+                default -> String.valueOf(c);
+            });
         }
         return sb.toString();
     }

src/protocol/http/src/main/java/org/apache/jmeter/protocol/http/visualizers/RequestViewHTTP.java

@@ -286,10 +286,10 @@ public class RequestViewHTTP implements RequestView {
     //TODO: move to utils class (JMeterUtils?)
     public static Map<String, String[]> getQueryMap(String query) {
 
-        Map<String, String[]> map = new HashMap<>();
-        String[] params = query.split(PARAM_CONCATENATE);
+        var map = new HashMap<String, String[]>();
+        var params = query.split(PARAM_CONCATENATE);
         for (String param : params) {
-            String[] paramSplit = param.split("=");
+            var paramSplit = param.split("=");
             if (paramSplit.length == 0) {
                 continue; // We found no key-/value-pair, so continue on the next param
             }

src/protocol/http/src/test/java/org/apache/jmeter/protocol/http/proxy/TestHttpRequestHdr.java

@@ -76,12 +76,13 @@ public class TestHttpRequestHdr extends JMeterTestCase {
         // A HTTP POST request
         contentEncoding = "UTF-8";
         String postBody = "update=yes&d=1&d=2&d=&d=&d=&d=&d=&d=1&d=2&d=1&d=&d=";
-        String testPostRequest = "POST " + url + " HTTP/1.0\n"
-                + "Content-type: "
-                + HTTPConstants.APPLICATION_X_WWW_FORM_URLENCODED + "\r\n"
-                + "Content-length: " + getBodyLength(postBody, contentEncoding) + "\r\n"
-                + "\r\n"
-                + postBody;
+        String testPostRequest = """
+                POST %s HTTP/1.0
+                Content-type: %s\r
+                Content-length: %d\r
+                \r
+                %s""".formatted(url, HTTPConstants.APPLICATION_X_WWW_FORM_URLENCODED, 
+                              getBodyLength(postBody, contentEncoding), postBody);
         s = getSamplerForRequest(url, testPostRequest, contentEncoding);
         assertEquals(HTTPConstants.POST, s.getMethod());
         assertFalse(s.getDoMultipart());
@@ -147,35 +148,37 @@ public class TestHttpRequestHdr extends JMeterTestCase {
         // The encoding should be picked up from the header we send with the request
         contentEncoding = "UTF-8";
         url =  "http://vmdal-hqqa9/retalixhq/GG_Implementation/ScreenEntity/ScreenEntityHTTP.aspx?Action=Save&ET=Vendor&TT=Single&Sid=1347280336092";
-        postBody = "<Action UIStatus=\"2\"><Vendor Id=\"9292\" HOST_ID=\"0\" VENDOR=\"9292\" TERMS_TYPE=\"No Terms\" TERMS=\"0 %\""
-                + " AUTO_PRICE=\"Use System Default\" VM_VENDOR_TYPE=\"DSD Vendor\" ITEM_FORMAT=\"PLU\" COST_ENTRY_SORT=\"UPC/EAN\""
-                + " VM_REPORT_SORT=\"UPC/EAN\" VM_ORDER_SORT=\"UPC/EAN\" VM_RECEIVING_SORT=\"UPC/EAN\" VM_MAX_BACK_ORDERS=\"99\""
-                + " MAX_OPEN_DAYS=\"99\" PAY_BASED_ON=\"System Cost\" ORDER_COST_DATE=\"Use System Rule\" VM_CONSIDER_FREE=\"False\""
-                + " VM_SHOW_DETAIL=\"False\" VM_UPDATE_COST=\"No\" RD_USE_VENDOR_CC=\"False\" BLIND_RECEIVING=\"Default\""
-                + " EXCLUDE_RECEIVED_COST=\"False\" PRINT_ITEM_ADJ=\"False\" PRINT_OVERALL_ADJ=\"False\" PRINT_TAX_DETAIL=\"False\""
-                + " BLOCK_PRICE_VIEW=\"False\" DELIVERY_STATUS=\"No Delivery\" AUTO_RECEIVE=\"False\" TARGET_GM_FLAG=\"%\""
-                + " MINIMUM_GM_FLAG=\"%\" MARGIN_TYPE=\"Gross Margin\" HOLD_REGULAR=\"Default\" HOLD_SPECIALS=\"Default\""
-                + " TRUSTING_VENDOR=\"False\" AUTO_ACCEPT=\"All\" EARLY_RCPT_AFFECTS=\"All Costs\" SBT_ELIGIBLE=\"Not eligible\""
-                + " SBT_REPORTING_DAY=\"Monday\" AUTO_BALANCE_FLAG=\"$\" DAX_MANAGED=\"False\" CHANGE_ID=\"QA\" CHANGE_SOURCE=\"Manual Change\""
-                + " ORIGINAL_SOURCE=\"Manual Change\" RECORD_STATUS=\"Add\" RECORD_STATUS_DATE=\"9/7/2012 8:34:58 AM\" VENDOR_NAME=\"test\""
-                + " UIStatus=\"2\"/></Action>";
-        testPostRequest = "POST " + url + " HTTP/1.1\r\n"
-                + "x-requested-with: XMLHttpRequest" + "\r\n"
-                + "Accept-Language: en-us" + "\r\n"
-                + "Referer: http://vmdal-hqqa9/retalixhq/GG_Implementation/ScreenEntity/ScreenEntityPage.aspx?ET=Vendor&TT=Single&"
-                + "WM=2&UID=9292&Sid=1347280331908&UITH=Blue&MUID=window_0" + "\r\n"
-                + "Accept: */*" + "\r\n"
-                + "Content-Type: application/x-www-form-urlencoded" + "\r\n"
-                + "Accept-Encoding: gzip, deflate" + "\r\n"
-                + "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729;"
-                + " .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; Tablet PC 2.0)" + "\r\n"
-                + "Host: vmdal-hqqa9" + "\r\n"
-                + "Content-Length: "+ getBodyLength(postBody, contentEncoding) + "\r\n"
-                + "Proxy-Connection: Keep-Alive" + "\r\n"
-                + "Pragma: no-cache" + "\r\n"
-                + "Cookie: RHQ=sid=5aaeb66c-e174-4f4c-9928-83cffcc62150" + "\r\n"
-                + "\r\n"
-                + postBody;
+        postBody = """
+                <Action UIStatus="2">
+                    <Vendor Id="9292" HOST_ID="0" VENDOR="9292" TERMS_TYPE="No Terms" TERMS="0 %"\
+                     AUTO_PRICE="Use System Default" VM_VENDOR_TYPE="DSD Vendor" ITEM_FORMAT="PLU" COST_ENTRY_SORT="UPC/EAN"\
+                     VM_REPORT_SORT="UPC/EAN" VM_ORDER_SORT="UPC/EAN" VM_RECEIVING_SORT="UPC/EAN" VM_MAX_BACK_ORDERS="99"\
+                     MAX_OPEN_DAYS="99" PAY_BASED_ON="System Cost" ORDER_COST_DATE="Use System Rule" VM_CONSIDER_FREE="False"\
+                     VM_SHOW_DETAIL="False" VM_UPDATE_COST="No" RD_USE_VENDOR_CC="False" BLIND_RECEIVING="Default"\
+                     EXCLUDE_RECEIVED_COST="False" PRINT_ITEM_ADJ="False" PRINT_OVERALL_ADJ="False" PRINT_TAX_DETAIL="False"\
+                     BLOCK_PRICE_VIEW="False" DELIVERY_STATUS="No Delivery" AUTO_RECEIVE="False" TARGET_GM_FLAG="%"\
+                     MINIMUM_GM_FLAG="%" MARGIN_TYPE="Gross Margin" HOLD_REGULAR="Default" HOLD_SPECIALS="Default"\
+                     TRUSTING_VENDOR="False" AUTO_ACCEPT="All" EARLY_RCPT_AFFECTS="All Costs" SBT_ELIGIBLE="Not eligible"\
+                     SBT_REPORTING_DAY="Monday" AUTO_BALANCE_FLAG="$" DAX_MANAGED="False" CHANGE_ID="QA" CHANGE_SOURCE="Manual Change"\
+                     ORIGINAL_SOURCE="Manual Change" RECORD_STATUS="Add" RECORD_STATUS_DATE="9/7/2012 8:34:58 AM" VENDOR_NAME="test"\
+                     UIStatus="2"/>
+                </Action>""";
+        testPostRequest = """
+                POST %s HTTP/1.1\r
+                x-requested-with: XMLHttpRequest\r
+                Accept-Language: en-us\r
+                Referer: http://vmdal-hqqa9/retalixhq/GG_Implementation/ScreenEntity/ScreenEntityPage.aspx?ET=Vendor&TT=Single&WM=2&UID=9292&Sid=1347280331908&UITH=Blue&MUID=window_0\r
+                Accept: */*\r
+                Content-Type: application/x-www-form-urlencoded\r
+                Accept-Encoding: gzip, deflate\r
+                User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; Tablet PC 2.0)\r
+                Host: vmdal-hqqa9\r
+                Content-Length: %d\r
+                Proxy-Connection: Keep-Alive\r
+                Pragma: no-cache\r
+                Cookie: RHQ=sid=5aaeb66c-e174-4f4c-9928-83cffcc62150\r
+                \r
+                %s""".formatted(url, getBodyLength(postBody, contentEncoding), postBody);
         // Use null for url to simulate that HttpRequestHdr do not
         // know the encoding for the page. Specify contentEncoding, so the
         // request is "sent" using that encoding
@@ -594,27 +597,34 @@ public class TestHttpRequestHdr extends JMeterTestCase {
     private String createMultipartFormBody(String titleValue, String descriptionValue,
             String contentEncoding, boolean includeExtraHeaders,
             String boundary, String endOfLine) {
-        // Title multipart
-        String postBody = "--" + boundary + endOfLine
-            + "Content-Disposition: form-data; name=\"title\"" + endOfLine;
-        if(includeExtraHeaders) {
-            postBody += "Content-Type: text/plain; charset=" + contentEncoding + endOfLine
-            + "Content-Transfer-Encoding: 8bit" + endOfLine;
-        }
-        postBody += endOfLine
-            + titleValue + endOfLine
-            + "--" + boundary + endOfLine;
-        // Description multipart
-        postBody += "Content-Disposition: form-data; name=\"description\"" + endOfLine;
-        if(includeExtraHeaders) {
-            postBody += "Content-Type: text/plain; charset=" + contentEncoding + endOfLine
-                + "Content-Transfer-Encoding: 8bit" + endOfLine;
-        }
-        postBody += endOfLine
-            + descriptionValue + endOfLine
-            + "--" + boundary + "--" + endOfLine;
-
-        return postBody;
+        
+        String titleHeaders = includeExtraHeaders ? """
+                Content-Type: text/plain; charset=%s%s\
+                Content-Transfer-Encoding: 8bit%s""".formatted(contentEncoding, endOfLine, endOfLine) : "";
+        
+        String descriptionHeaders = includeExtraHeaders ? """
+                Content-Type: text/plain; charset=%s%s\
+                Content-Transfer-Encoding: 8bit%s""".formatted(contentEncoding, endOfLine, endOfLine) : "";
+        
+        return """
+                --%s%s\
+                Content-Disposition: form-data; name="title"%s\
+                %s%s\
+                %s%s\
+                --%s%s\
+                Content-Disposition: form-data; name="description"%s\
+                %s%s\
+                %s%s\
+                --%s--%s""".formatted(
+                    boundary, endOfLine,
+                    endOfLine,
+                    titleHeaders, endOfLine,
+                    titleValue, endOfLine,
+                    boundary, endOfLine,
+                    endOfLine,
+                    descriptionHeaders, endOfLine,
+                    descriptionValue, endOfLine,
+                    boundary, endOfLine);
     }
 
     private String createMultipartFileUploadBody(String fileField, String fileName,

src/protocol/http/src/test/java/org/apache/jmeter/protocol/http/util/TestGraphQLRequestParamUtils.java

@@ -45,23 +45,25 @@ class TestGraphQLRequestParamUtils {
 
     private static final String OPERATION_NAME = "";
 
-    private static final String QUERY =
-            "query($id: ID!) {\n"
-            + "  droid(id: $id) {\n"
-            + "    id\n"
-            + "    name\n"
-            + "    friends {\n"
-            + "      id\n"
-            + "      name\n"
-            + "      appearsIn\n"
-            + "    }\n"
-            + "  }\n"
-            + "}\n";
+    private static final String QUERY = """
+            query($id: ID!) {
+              droid(id: $id) {
+                id
+                name
+                friends {
+                  id
+                  name
+                  appearsIn
+                }
+              }
+            }
+            """;
 
-    private static final String VARIABLES =
-            "{\n"
-            + "  \"id\": \"2001\"\n"
-            + "}\n";
+    private static final String VARIABLES = """
+            {
+              "id": "2001"
+            }
+            """;
 
     private static final String EXPECTED_QUERY_GET_PARAM_VALUE =
             "query($id: ID!) { droid(id: $id) { id name friends { id name appearsIn } } }";

src/protocol/jdbc/src/main/java/org/apache/jmeter/protocol/jdbc/config/DataSourceElement.java

@@ -164,8 +164,7 @@ public class DataSourceElement extends AbstractTestElement
     public static String getConnectionInfo(String poolName) throws SQLException{
         Object poolObject =
                 JMeterContextService.getContext().getVariables().getObject(poolName);
-        if (poolObject instanceof DataSourceComponentImpl) {
-            DataSourceComponentImpl pool = (DataSourceComponentImpl) poolObject;
+        if (poolObject instanceof DataSourceComponentImpl pool) {
             return pool.getConnectionInfo();
         } else {
             return "Object:" + poolName + " is not of expected type '" + DataSourceComponentImpl.class.getName() + "'";
@@ -194,8 +193,7 @@ public class DataSourceElement extends AbstractTestElement
         if (poolObject == null) {
             throw new SQLException("No pool found named: '" + poolName + "', ensure Variable Name matches Variable Name of JDBC Connection Configuration");
         } else {
-            if(poolObject instanceof DataSourceComponentImpl) {
-                DataSourceComponentImpl pool = (DataSourceComponentImpl) poolObject;
+            if(poolObject instanceof DataSourceComponentImpl pool) {
                 return pool.getConnection();
             } else {
                 String errorMsg = "Found object stored under variable:'" + poolName + "' with class:"

src/protocol/jms/src/main/java/org/apache/jmeter/protocol/jms/sampler/JMSSampler.java

@@ -307,8 +307,8 @@ public class JMSSampler extends AbstractSampler implements ThreadListener {
         if (replyMsg == null) {
             res.setResponseMessage("No reply message received");
         } else {
-            if (replyMsg instanceof TextMessage) {
-                res.setResponseData(((TextMessage) replyMsg).getText(), null);
+            if (replyMsg instanceof TextMessage textMessage) {
+                res.setResponseData(textMessage.getText(), null);
             } else {
                 res.setResponseData(replyMsg.toString(), null);
             }
@@ -355,20 +355,17 @@ public class JMSSampler extends AbstractSampler implements ThreadListener {
     private static void extractContent(StringBuilder buffer, StringBuilder propBuffer, Message msg) {
         if (msg != null) {
             try {
-                if (msg instanceof TextMessage) {
-                    buffer.append(((TextMessage) msg).getText());
-                } else if (msg instanceof ObjectMessage) {
-                    ObjectMessage objectMessage = (ObjectMessage) msg;
+                if (msg instanceof TextMessage textMessage) {
+                    buffer.append(textMessage.getText());
+                } else if (msg instanceof ObjectMessage objectMessage) {
                     if (objectMessage.getObject() != null) {
                         buffer.append(objectMessage.getObject().getClass());
                     } else {
                         buffer.append("object is null");
                     }
-                } else if (msg instanceof BytesMessage) {
-                    BytesMessage bytesMessage = (BytesMessage) msg;
+                } else if (msg instanceof BytesMessage bytesMessage) {
                     buffer.append(bytesMessage.getBodyLength() + " bytes received in BytesMessage");
-                } else if (msg instanceof MapMessage) {
-                    MapMessage mapm = (MapMessage) msg;
+                } else if (msg instanceof MapMessage mapm) {
                     @SuppressWarnings("unchecked") // MapNames are Strings
                     Enumeration<String> enumb = mapm.getMapNames();
                     while (enumb.hasMoreElements()) {
@@ -484,8 +481,8 @@ public class JMSSampler extends AbstractSampler implements ThreadListener {
         Object o = getProperty(JMS_PROPERTIES).getObjectValue();
         JMSProperties jmsProperties = null;
         // Backward compatibility with versions <= 2.10
-        if (o instanceof Arguments) {
-            jmsProperties = Utils.convertArgumentsToJmsProperties((Arguments) o);
+        if (o instanceof Arguments arguments) {
+            jmsProperties = Utils.convertArgumentsToJmsProperties(arguments);
         } else {
             jmsProperties = (JMSProperties) o;
         }