1--- ../../../libcore/ojluni/src/main/java/java/util/AbstractCollection.java 2019-05-31 10:36:26.634361294 -0700 2+++ src-ex/java/util/AbstractCollection.java 2019-11-18 13:04:48.253575013 -0800 3@@ -63,7 +63,13 @@ 4 * Sole constructor. (For invocation by subclass constructors, typically 5 * implicit.) 6 */ 7+ public static volatile int TOTAL_COUNT; 8+ public int cnt; 9+ 10 protected AbstractCollection() { 11+ synchronized (Collection.class) { 12+ cnt = ++TOTAL_COUNT; 13+ } 14 } 15 16 // Query Operations 17