code: public void set(final Exception e) {
  		if (this.value.compareAndSet(null, e)) {
  			this.listeners.clear();
  			this.cdl.countDown();
  		}
  	}
docs: The get() method throws this exception wrapped as the cause of an ExecutionException.<br>
  Multiple calls are ignored.<br>
  Calls after cancel are ignored.
  
  @param e Exception