Use Map.computeIfAbsent where appropriate

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/scope/context/JobContext.java

@@ -107,11 +107,7 @@ public Map<String, Object> getJobParameters() {
 	 */
 	public void registerDestructionCallback(String name, Runnable callback) {
 		synchronized (callbacks) {
-			Set<Runnable> set = callbacks.get(name);
-			if (set == null) {
-				set = new HashSet<>();
-				callbacks.put(name, set);
-			}
+			Set<Runnable> set = callbacks.computeIfAbsent(name, k -> new HashSet<>());
 			set.add(callback);
 		}
 	}

spring-batch-core/src/main/java/org/springframework/batch/core/scope/context/StepContext.java

@@ -147,11 +147,7 @@ public Map<String, Object> getJobParameters() {
 	 */
 	public void registerDestructionCallback(String name, Runnable callback) {
 		synchronized (callbacks) {
-			Set<Runnable> set = callbacks.get(name);
-			if (set == null) {
-				set = new HashSet<>();
-				callbacks.put(name, set);
-			}
+			Set<Runnable> set = callbacks.computeIfAbsent(name, k -> new HashSet<>());
 			set.add(callback);
 		}
 	}

spring-batch-infrastructure/src/main/java/org/springframework/batch/repeat/context/RepeatContextSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -125,11 +125,7 @@ public synchronized int getStartedCount() {
 	@Override
 	public void registerDestructionCallback(String name, Runnable callback) {
 		synchronized (callbacks) {
-			Set<Runnable> set = callbacks.get(name);
-			if (set == null) {
-				set = new HashSet<>();
-				callbacks.put(name, set);
-			}
+			Set<Runnable> set = callbacks.computeIfAbsent(name, k -> new HashSet<>());
 			set.add(callback);
 		}
 	}