code: public Jump<T> setJumpDescriptor (JumpDescriptor<T> jumpDescriptor) {
  		this.jumpDescriptor = jumpDescriptor;
  		this.target = null;
  		this.isJumpAchievable = false;
  		return this;
  	}
docs: Sets the jump descriptor to use.
  @param jumpDescriptor the jump descriptor to set
  @return this behavior for chaining.