AbstractQueuedSynchronizer and AbstractQueuedLongSynchronizer
handle exceptions during acquire like this

try { ... }
catch (RuntimeException e) { handle(); throw e; }

This fails to handle errors or other pathological throwables
(e.g. a checked Exception can always be thrown using Thread.stop(Throwable))

More robust and clear is to use the idiom

boolean failed = true;
try { ... ; failed = false; }
finally { if (failed) handle(); }