The code synchronizes on a boxed primitive constant, such as an Boolean.

private static Boolean inited = Boolean.FALSE;
...
  synchronized(inited) { 
    if (!inited) {
       init();
       inited = Boolean.TRUE;
       }
     }
...

Since there normally exist only two Boolean objects, this code could be synchronizing on the same object as other, unrelated code, leading to unresponsiveness and possible deadlock