--- ../../../libcore/ojluni/src/main/java/java/util/AbstractCollection.java	2019-05-31 10:36:26.634361294 -0700
+++ src-ex/java/util/AbstractCollection.java	2019-11-18 13:04:48.253575013 -0800
@@ -63,7 +63,13 @@
      * Sole constructor.  (For invocation by subclass constructors, typically
      * implicit.)
      */
+    public static volatile int TOTAL_COUNT;
+    public int cnt;
+
     protected AbstractCollection() {
+      synchronized (Collection.class) {
+        cnt = ++TOTAL_COUNT;
+      }
     }
 
     // Query Operations