GH-11042: Fix race condition in the ControlBusCommandRegistry (#11046)

* GH-11042: Fix race condition in the ControlBusCommandRegistry

Fixes: #11042

The `ControlBusCommandRegistry` can be accessed (and populated) concurrently.
Therefore, it is better to protect its internal from the `ConcurrentModificationException`

* Use `ConcurrentHashMap` and `synchronized` in the `ControlBusCommandRegistry`
whenever concurrent access is possible.

**Auto-cherry-pick to `7.0.x` & `6.5.x`**

* No need in `synchronized (this.controlBusCommands)`

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/support/management/ControlBusCommandRegistry.java

@@ -24,6 +24,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -71,7 +72,7 @@ public class ControlBusCommandRegistry
 
 	private static final ControlBusMethodFilter CONTROL_BUS_METHOD_FILTER = new ControlBusMethodFilter();
 
-	private final Map<String, Map<CommandMethod, Expression>> controlBusCommands = new HashMap<>();
+	private final Map<String, Map<CommandMethod, Expression>> controlBusCommands = new ConcurrentHashMap<>();
 
 	private boolean eagerInitialization;
 
@@ -195,7 +196,7 @@ private Expression populateCommandMethod(CommandMethod commandMethod,
 		String beanName = commandMethod.beanName;
 
 		Map<CommandMethod, Expression> beanControlBusCommands =
-				this.controlBusCommands.computeIfAbsent(beanName, (key) -> new HashMap<>());
+				this.controlBusCommands.computeIfAbsent(beanName, (key) -> new ConcurrentHashMap<>());
 
 		try {
 			return beanControlBusCommands.computeIfAbsent(commandMethod, mappingFunction);