ScheduledFutureTask(Runnable r,V result,long ns,long period){
  super(r,result);
  this.time=ns;
  this.period=period;
  this.sequenceNumber=sequencer.getAndIncrement();
}

ScheduledFutureTask ( Runnable r , V result , long ns , long period ) { super ( r , result ) ; this . time = ns ; this . period = period ; this . sequenceNumber = sequencer . getAndIncrement ( ) ; }
creates a periodic action with given nano time and period .
