/guava/guava/src/com/google/common/collect/ConcurrentHashMultiset.java
int newValue = Math.max( , oldValue - occurrences) ;
int newValue = Math.max ( 0, oldValue - occurrences ) ;
if (existingCounter == null) { return 0; } while (true) { int oldValue = existingCounter.get(); if (oldValue != 0) { <extra_id_0> if (existingCounter.compareAndSet(oldValue, newValue)) { if (newValue == 0) { countMap.remove(element, existingCounter); } return oldValue; }