[pinpoint-apm#9932] Cleanup

Author: emeroad

collector/src/main/java/com/navercorp/pinpoint/collector/cluster/ClusterPointRepository.java

@@ -22,6 +22,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import javax.annotation.concurrent.GuardedBy;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -33,6 +34,7 @@ public class ClusterPointRepository<T extends ClusterPoint<?>> implements Cluste
 
     private final Logger logger = LogManager.getLogger(this.getClass());
 
+    @GuardedBy("this")
     private final Map<ClusterKey, Set<T>> clusterPointRepository = new HashMap<>();
 
     public boolean addAndIsKeyCreated(T clusterPoint) {