Yahoo! Answers homework help for question: "Desperate java gridworld issues, help!!!?"

TeleporterActor.java

import info.gridworld.actor.Actor;
import info.gridworld.actor.ActorWorld;
import info.gridworld.grid.Grid;
import info.gridworld.grid.Location;

import java.awt.Color;

/**
 * Yahoo! Answers homework help for question: "Desperate java gridworld issues, help!!!?"
 *   http://answers.yahoo.com/question/index?qid=20131010175243AAMJlkA
 *   ( Official & newer unofficial GridWorld library jar: http://horstmann.com/gridworld/ ) 
 * 
 * Question:
 *  "So i have to make an Actor that will teleport when i call the method. 
 *   However, 
 *   	1.) i can't make the default constructor
 * 		2.) I keep getting a Null Pointer error. 
 *   It complies, but doesn't run as intended. Please help. My code is below:"
 *  
 * @author wrestler
 *
 */
public class TeleporterActor extends Actor {
	
	Location loc = getLocation(); 
	
	// FIXME: If getGrid() called here, gr will be null when act() called.
	//        See how Bug.java calls getGrid() right before calling 
	//        move(), etc. since putSelfInGrid() has been called by then. 
	Grid<Actor> gr = getGrid(); 
	
	// make a default constructor that sets the direction to WEST
	public void TeleporterActor() { // TODO: Remove "void" to make this a default constructor.
		 
	}

	// make an initialization constructor that receives a direction
	public TeleporterActor(int dir) {
		int dir1 = dir;
		dir1 = getDirection();
	}

	private Location getRandomLocation() {
		
		// Is this what you had?  Yahoo! Answers cut off the second parameter's "Math...".
		Location loc1 = new Location((int) (Math.random() * 7)
	                                ,(int) (Math.random() * 7));
		
		return loc1;
	}

	// the act method will move this actor to a random location
	// as long as that location is valid and empty
	/* FIXME: See "getGrid()" hint above Clicking on "Step" or "Run" button causes this NPE:
	 * 
	 *   Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	 *           at TeleporterActor.act(TeleporterActor.java:63)
	 *           at info.gridworld.actor.ActorWorld.step(ActorWorld.java:69)
	 *           ...etc.
	 */
	public void act() {

		if (gr.isValid(getRandomLocation())) {
			moveTo(getRandomLocation());
		} else {
			moveTo(getLocation());
		}

	}

	public Color getColor() {
		return null;
	}

	/**
	 * Program starting point: Based on main() in GridWorld's initial "BugRunner.java" example.
	 * @param args
	 * @throws InterruptedException
	 */
	public static void main(String[] args) throws InterruptedException {
		
		ActorWorld world = new ActorWorld();
		world.add(new TeleporterActor(Location.WEST));
		world.show();
	}

}

I need the answers