src/java.base/share/classes/java/lang/ref/Finalizer.java

*** 28,37 ****
--- 28,40 ----
  import java.security.PrivilegedAction;
  import java.security.AccessController;
  import sun.misc.JavaLangAccess;
  import sun.misc.SharedSecrets;
  import sun.misc.VM;
+ import java.util.TreeMap;
+ import java.util.Set;
+ import java.util.Map;
  
  final class Finalizer extends FinalReference<Object> { /* Package-private; must be in
                                                            same package as the Reference
                                                            class */
  
*** 85,94 ****
--- 88,127 ----
      /* Invoked by VM */
      static void register(Object finalizee) {
          new Finalizer(finalizee);
      }
  
+     static String printFinalizationQueue() {
+         Finalizer tmp = unfinalized;
+         Map <String, Integer> countMap = new TreeMap<String, Integer>();
+         synchronized (lock) {
+            while(tmp != null) {
+               Object referent = tmp.get();
+               if (referent != null) {
+                   Class<?> objClass = referent.getClass();
+                   String className = objClass.getName();
+                   Integer cnt = countMap.get(className);
+                   if (cnt == null) {
+                       countMap.put(className,1);
+                   }
+                   else {
+                       countMap.put(className,cnt + 1);
+                   }
+               }
+               tmp = tmp.next;
+            }
+         }
+ 
+         StringBuilder sb = new StringBuilder();
+         Set<String> keys = countMap.keySet();
+         for (String key : keys) {
+             sb.append("Class: " + key + " count: "  + countMap.get(key) + "\n");
+         }
+ 
+         return sb.toString();
+     }
+ 
      private void runFinalizer(JavaLangAccess jla) {
          synchronized (this) {
              if (hasBeenFinalized()) return;
              remove();
          }