public static TaskContext current(){
  final Deque<TaskContext> stack=contextStacks.get();
  if (stack == null) {
    return null;
  }
  return stack.peekLast();
}

public static TaskContext current ( ) { final Deque < TaskContext > stack = contextStacks . get ( ) ; if ( stack == null ) { return null ; } return stack . peekLast ( ) ; }
gets the current execution context for this thread from the stack .
