Add missing @Override annotations

This commit also adds MissingOverrideCheck module to Checkstyle configuration.

messaging/src/main/java/org/springframework/security/messaging/util/matcher/MessageMatcher.java

@@ -36,10 +36,12 @@ public interface MessageMatcher<T> {
 	 * Matches every {@link Message}
 	 */
 	MessageMatcher<Object> ANY_MESSAGE = new MessageMatcher<Object>() {
+		@Override
 		public boolean matches(Message<? extends Object> message) {
 			return true;
 		}
 
+		@Override
 		public String toString() {
 			return "ANY_MESSAGE";
 		}

messaging/src/main/java/org/springframework/security/messaging/util/matcher/SimpMessageTypeMatcher.java

@@ -44,6 +44,7 @@ public class SimpMessageTypeMatcher implements MessageMatcher<Object> {
 		this.typeToMatch = typeToMatch;
 	}
 
+	@Override
 	public boolean matches(Message<? extends Object> message) {
 		MessageHeaders headers = message.getHeaders();
 		SimpMessageType messageType = SimpMessageHeaderAccessor.getMessageType(headers);
@@ -64,6 +65,7 @@ public class SimpMessageTypeMatcher implements MessageMatcher<Object> {
 
 	}
 
+	@Override
 	public int hashCode() {
 		// Using nullSafeHashCode for proper array hashCode handling
 		return ObjectUtils.nullSafeHashCode(this.typeToMatch);
@@ -73,4 +75,4 @@ public class SimpMessageTypeMatcher implements MessageMatcher<Object> {
 	public String toString() {
 		return "SimpMessageTypeMatcher [typeToMatch=" + typeToMatch + "]";
 	}
-}
+}