question: public static void onGridStop ( ) throws InterruptedException { synchronized ( mux ) { if ( gridCnt == 0 ) return ; -- gridCnt ; Thread timer0 = timer ; if ( gridCnt == 0 && timer0 != null ) { timer = null ; timer0 . interrupt ( ) ; timer0 . join ( ) ; } } }
target:  Stops clock timer if all nodes into JVM were stopped.