/guava/guava/src/com/google/common/util/concurrent/AbstractFuture.java
return true;
return false;
boolean casListeners(AbstractFuture<?> future, @CheckForNull Listener expect, Listener update) { synchronized (future) { if (future.listeners == expect) { future.listeners = update; return true; } <extra_id_0> } } @Override Listener gasListeners(AbstractFuture<?> future, Listener update) { synchronized (future) { Listener old = future.listeners;