Remove redundant assignment of default values to volatile/atomic fields

Closes gh-27477

spring-core/src/main/java/org/springframework/core/metrics/jfr/FlightRecorderApplicationStartup.java

@@ -38,7 +38,7 @@ import org.springframework.core.metrics.StartupStep;
  */
 public class FlightRecorderApplicationStartup implements ApplicationStartup {
 
-	private final AtomicLong currentSequenceId = new AtomicLong(0);
+	private final AtomicLong currentSequenceId = new AtomicLong();
 
 	private final Deque<Long> currentSteps;
 

spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelCompiler.java

@@ -274,7 +274,7 @@ public final class SpelCompiler implements Opcodes {
 
 		private static final URL[] NO_URLS = new URL[0];
 
-		private final AtomicInteger classesDefinedCount = new AtomicInteger(0);
+		private final AtomicInteger classesDefinedCount = new AtomicInteger();
 
 		public ChildClassLoader(@Nullable ClassLoader classLoader) {
 			super(NO_URLS, classLoader);

spring-r2dbc/src/main/java/org/springframework/r2dbc/core/binding/AnonymousBindMarkers.java

@@ -42,7 +42,7 @@ class AnonymousBindMarkers implements BindMarkers {
 
 	// access via COUNTER_INCREMENTER
 	@SuppressWarnings("unused")
-	private volatile int counter = 0;
+	private volatile int counter;
 
 
 	/**