diff --git a/core/spring-boot-test/src/main/java/org/springframework/boot/test/json/JsonContentAssert.java b/core/spring-boot-test/src/main/java/org/springframework/boot/test/json/JsonContentAssert.java
index dde95b3ece3..93ce0da1ef1 100644
--- a/core/spring-boot-test/src/main/java/org/springframework/boot/test/json/JsonContentAssert.java
+++ b/core/spring-boot-test/src/main/java/org/springframework/boot/test/json/JsonContentAssert.java
@@ -42,6 +42,7 @@ import org.skyscreamer.jsonassert.comparator.JSONComparator;
 import org.springframework.core.io.Resource;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
+import org.springframework.util.function.ThrowingFunction;
 
 /**
  * AssertJ {@link Assert} for {@link JsonContent}.
@@ -997,24 +998,17 @@ public class JsonContentAssert extends AbstractAssert<JsonContentAssert, CharSeq
 	}
 
 	private JSONCompareResult compare(@Nullable CharSequence expectedJson, JSONCompareMode compareMode) {
-		if (this.actual == null) {
-			return compareForNull(expectedJson);
-		}
-		if (expectedJson == null) {
-			return fail("Expected JSON but got null");
-		}
-		try {
-			return JSONCompare.compareJSON(expectedJson.toString(), this.actual.toString(), compareMode);
-		}
-		catch (Exception ex) {
-			if (ex instanceof RuntimeException runtimeException) {
-				throw runtimeException;
-			}
-			throw new IllegalStateException(ex);
-		}
+		return compare(expectedJson,
+				(expected) -> JSONCompare.compareJSON(expected, this.actual.toString(), compareMode));
 	}
 
 	private JSONCompareResult compare(@Nullable CharSequence expectedJson, JSONComparator comparator) {
+		return compare(expectedJson,
+				(expected) -> JSONCompare.compareJSON(expected, this.actual.toString(), comparator));
+	}
+
+	private JSONCompareResult compare(@Nullable CharSequence expectedJson,
+			ThrowingFunction<String, JSONCompareResult> compareAction) {
 		if (this.actual == null) {
 			return compareForNull(expectedJson);
 		}
@@ -1022,7 +1016,7 @@ public class JsonContentAssert extends AbstractAssert<JsonContentAssert, CharSeq
 			return fail("Expected JSON but got null");
 		}
 		try {
-			return JSONCompare.compareJSON(expectedJson.toString(), this.actual.toString(), comparator);
+			return compareAction.applyWithException(expectedJson.toString());
 		}
 		catch (Exception ex) {
 			if (ex instanceof RuntimeException runtimeException) {
diff --git a/core/spring-boot-test/src/main/java/org/springframework/boot/test/system/OutputCaptureRule.java b/core/spring-boot-test/src/main/java/org/springframework/boot/test/system/OutputCaptureRule.java
index aa5a6fb9e4a..6171f5ac726 100644
--- a/core/spring-boot-test/src/main/java/org/springframework/boot/test/system/OutputCaptureRule.java
+++ b/core/spring-boot-test/src/main/java/org/springframework/boot/test/system/OutputCaptureRule.java
@@ -52,7 +52,7 @@ import static org.hamcrest.Matchers.allOf;
  * @since 2.2.0
  * @deprecated since 4.0.0 in favor of JUnit 5 and {@link OutputCaptureExtension}
  */
-@Deprecated(since = "4.0.0")
+@Deprecated(since = "4.0.0", forRemoval = true)
 public class OutputCaptureRule implements TestRule, CapturedOutput {
 
 	private final OutputCapture delegate = new OutputCapture();
diff --git a/core/spring-boot-test/src/test/java/org/springframework/boot/test/system/OutputCaptureRuleTests.java b/core/spring-boot-test/src/test/java/org/springframework/boot/test/system/OutputCaptureRuleTests.java
index ace537bc7f8..8f4b2704e79 100644
--- a/core/spring-boot-test/src/test/java/org/springframework/boot/test/system/OutputCaptureRuleTests.java
+++ b/core/spring-boot-test/src/test/java/org/springframework/boot/test/system/OutputCaptureRuleTests.java
@@ -26,7 +26,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Roland Weisleder
  */
-@SuppressWarnings("deprecation")
+@SuppressWarnings("removal")
 public class OutputCaptureRuleTests {
 
 	@Rule
diff --git a/core/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java b/core/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java
index a3fdea3e978..6e941a3e167 100644
--- a/core/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java
+++ b/core/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java
@@ -176,10 +176,10 @@ public class Log4J2LoggingSystem extends AbstractLoggingSystem {
 		LoggerContext loggerContext = getLoggerContext();
 		String contextName = loggerContext.getName();
 		List<String> extensions = getStandardConfigExtensions();
-		extensions.forEach((e) -> locations.add("log4j2-test" + contextName + e));
-		extensions.forEach((e) -> locations.add("log4j2-test" + e));
-		extensions.forEach((e) -> locations.add("log4j2" + contextName + e));
-		extensions.forEach((e) -> locations.add("log4j2" + e));
+		addLocation(locations, "log4j2-test" + contextName, extensions);
+		addLocation(locations, "log4j2-test", extensions);
+		addLocation(locations, "log4j2" + contextName, extensions);
+		addLocation(locations, "log4j2", extensions);
 	}
 
 	private List<String> getStandardConfigExtensions() {
@@ -188,22 +188,26 @@ public class Log4J2LoggingSystem extends AbstractLoggingSystem {
 		ClassLoader classLoader = LoggerContext.class.getClassLoader();
 		// The order of the extensions corresponds to the order in which Log4j Core 2 and
 		// 3 will try to load them, in decreasing value of @Order.
-		if (isClassAvailable(classLoader, PROPS_CONFIGURATION_FACTORY_V2)
-				|| isClassAvailable(classLoader, PROPS_CONFIGURATION_FACTORY_V3)) {
+		if (isPresent(classLoader, PROPS_CONFIGURATION_FACTORY_V2)
+				|| isPresent(classLoader, PROPS_CONFIGURATION_FACTORY_V3)) {
 			extensions.add(".properties");
 		}
-		if (areAllClassesAvailable(classLoader, YAML_CONFIGURATION_FACTORY_V2, YAML_TREE_PARSER_V2)
-				|| isClassAvailable(classLoader, YAML_CONFIGURATION_FACTORY_V3)) {
+		if (isPresent(classLoader, YAML_CONFIGURATION_FACTORY_V2, YAML_TREE_PARSER_V2)
+				|| isPresent(classLoader, YAML_CONFIGURATION_FACTORY_V3)) {
 			Collections.addAll(extensions, ".yaml", ".yml");
 		}
-		if (isClassAvailable(classLoader, JSON_TREE_PARSER_V2) || isClassAvailable(classLoader, JSON_TREE_PARSER_V3)) {
+		if (isPresent(classLoader, JSON_TREE_PARSER_V2) || isPresent(classLoader, JSON_TREE_PARSER_V3)) {
 			Collections.addAll(extensions, ".json", ".jsn");
 		}
 		extensions.add(".xml");
 		return extensions;
 	}
 
-	private boolean areAllClassesAvailable(ClassLoader classLoader, String... classNames) {
+	private void addLocation(List<String> locations, String location, List<String> extensions) {
+		extensions.forEach((extension) -> locations.add(location + extension));
+	}
+
+	private boolean isPresent(ClassLoader classLoader, String... classNames) {
 		for (String className : classNames) {
 			if (!isClassAvailable(classLoader, className)) {
 				return false;
@@ -212,15 +216,15 @@ public class Log4J2LoggingSystem extends AbstractLoggingSystem {
 		return true;
 	}
 
+	protected boolean isClassAvailable(ClassLoader classLoader, String className) {
+		return ClassUtils.isPresent(className, classLoader);
+	}
+
 	@Deprecated(since = "4.0.0", forRemoval = true)
 	protected boolean isClassAvailable(String className) {
 		return ClassUtils.isPresent(className, getClassLoader());
 	}
 
-	protected boolean isClassAvailable(ClassLoader classLoader, String className) {
-		return ClassUtils.isPresent(className, classLoader);
-	}
-
 	@Override
 	public void beforeInitialize() {
 		LoggerContext loggerContext = getLoggerContext();
diff --git a/module/spring-boot-data-mongodb/src/main/java/org/springframework/boot/data/mongodb/autoconfigure/MongoDataConfiguration.java b/module/spring-boot-data-mongodb/src/main/java/org/springframework/boot/data/mongodb/autoconfigure/MongoDataConfiguration.java
index 923f4c72fdc..4838cf18a44 100644
--- a/module/spring-boot-data-mongodb/src/main/java/org/springframework/boot/data/mongodb/autoconfigure/MongoDataConfiguration.java
+++ b/module/spring-boot-data-mongodb/src/main/java/org/springframework/boot/data/mongodb/autoconfigure/MongoDataConfiguration.java
@@ -32,7 +32,7 @@ import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
-import org.springframework.data.mongodb.core.convert.MongoCustomConversions.BigDecimalRepresentation;
+import org.springframework.data.mongodb.core.convert.MongoCustomConversions.MongoConverterConfigurationAdapter;
 import org.springframework.data.mongodb.core.convert.NoOpDbRefResolver;
 import org.springframework.data.mongodb.core.mapping.Document;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
@@ -77,12 +77,11 @@ class MongoDataConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	MongoCustomConversions mongoCustomConversions() {
-		return MongoCustomConversions.create((configurer) -> {
-			BigDecimalRepresentation bigDecimaRepresentation = this.properties.getRepresentation().getBigDecimal();
-			if (bigDecimaRepresentation != null) {
-				configurer.bigDecimal(bigDecimaRepresentation);
-			}
-		});
+		return MongoCustomConversions.create(this::configureConversions);
+	}
+
+	private void configureConversions(MongoConverterConfigurationAdapter configurer) {
+		PropertyMapper.get().from(this.properties.getRepresentation()::getBigDecimal).to(configurer::bigDecimal);
 	}
 
 	@Bean
diff --git a/module/spring-boot-http-converter/src/test/java/org/springframework/boot/http/converter/autoconfigure/HttpMessageConvertersAutoConfigurationTests.java b/module/spring-boot-http-converter/src/test/java/org/springframework/boot/http/converter/autoconfigure/HttpMessageConvertersAutoConfigurationTests.java
index 673b8b83f4a..3e434379d27 100644
--- a/module/spring-boot-http-converter/src/test/java/org/springframework/boot/http/converter/autoconfigure/HttpMessageConvertersAutoConfigurationTests.java
+++ b/module/spring-boot-http-converter/src/test/java/org/springframework/boot/http/converter/autoconfigure/HttpMessageConvertersAutoConfigurationTests.java
@@ -324,9 +324,7 @@ class HttpMessageConvertersAutoConfigurationTests {
 
 	private void assertConvertersBeanRegisteredWithHttpMessageConverters(AssertableApplicationContext context,
 			List<Class<? extends HttpMessageConverter<?>>> types) {
-
 		List<? extends HttpMessageConverter<?>> converterInstances = types.stream().map(context::getBean).toList();
-
 		HttpMessageConverters converters = context.getBean(HttpMessageConverters.class);
 		assertThat(converters.getConverters()).containsSubsequence(converterInstances);
 	}