Java Code

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;

import javax.swing.*;
import java.util.*;
public class GameImgBkg extends JApplet implements Runnable, KeyListener
{
	int width, height;		// dimensions of game
	ArrayList<Rectangle> walls;
	BufferedImage backgroundBuf, screenBuf;		// screenBuf = draw backgrd then player and entities in layers
	Graphics2D background;
	MediaTracker track;
	Sprite player;
	Sprite fairy;	
	Thing exit;
	Thread thread;
	Random random;
	Image bkdrop;
	public void init( )
	{
		resize( 300, 300 );
		loadImages( );
		width = this.getWidth( );
		height = this.getHeight( );

		walls = new ArrayList<Rectangle>( );
		buildWalls( );

        player.setLocation( 50, 50 );
        fairy.setLocation ( width-70, height-70 );
        random = new Random( );
        try {
        	track.waitForAll( );
        } catch ( Exception e ) { };
		addKeyListener(this);
	}
	public void start( )
	{
		thread = new Thread( this );
		thread.start( );
		setFocusable(true);		
	}
    public  BufferedImage createBufImage (int width, int height) {
    	return GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration().createCompatibleImage(width, height, Transparency.BITMASK);	
    }
    public void loadImages( )
    {
    	track = new MediaTracker( this ); 
       	Image img = getImage( getCodeBase( ), "stand_front.gif" );
    	Image back = getImage( getCodeBase( ), "walk_back.gif" );
    	Image front = getImage( getCodeBase( ), "walk_front.gif" );
    	Image right = getImage( getCodeBase( ), "walk_right.gif" );
    	Image left = getImage( getCodeBase( ), "walk_left.gif" );
    	bkdrop = getImage( getCodeBase( ), "DungeonBkdrop.jpg");
    	
    	track.addImage(img, 2);      track.addImage(back, 6 );
    	track.addImage( front, 3 );  track.addImage( left, 4 );
    	track.addImage( right, 5 );
    	track.addImage( bkdrop, 6 );
    	
    	player = new Sprite( img, back, front, left, right );
    	img = getImage( getCodeBase( ), "Fairy.gif" );
    	track.addImage( img, 7 );
    	fairy = new Sprite( img );
    	fairy.speed = 2;
    	exit = new Thing( getImage( getCodeBase( ), "door.jpg"));
   }
	public void buildWalls( )
	{
		// create Polygon or Rectangle objects and store in ArrayList walls
		int wallThickness = 10;
		walls.add( new Rectangle( 0,0, width, wallThickness ) ); 		// top
		walls.add( new Rectangle( 0,0, wallThickness, height ) ); 		// left
		walls.add( new Rectangle( width-wallThickness,0, wallThickness, height ) ); 		// right
		walls.add( new Rectangle( 0,height-wallThickness, width, wallThickness ) ); 		// bottom
		
		walls.add( new Rectangle( 0,100, 100, wallThickness ) ); 		// left
		// bottom wall structure
		walls.add( new Rectangle( 50,height-wallThickness-120, wallThickness, 70 ) );  	// vert on left 		
		walls.add( new Rectangle( 50,height-wallThickness-120, width-150, wallThickness ) ); 		// horiz top
		walls.add( new Rectangle( 50,height-wallThickness-50, width-120, wallThickness ) ); 		// horiz bottom
		walls.add( new Rectangle( 200,height-230, wallThickness, 130 ) ); 			// vert on rt
		
		exit.setLocation( 50+wallThickness,height-wallThickness-50-60);
	}
	public boolean checkCollisionWalls( Rectangle entityAura )
	{
		for ( int i=0; i< walls.size( ); i++ )
		{
			if ( entityAura.intersects( walls.get( i ) ))
				return true;
		}
		return false;
	}
	public boolean checkCollisionFairy(  )
	{
		return player.getDimensions( ).intersects( fairy.getDimensions( ) );
	}
	public void paintWalls(  )
	{
 		backgroundBuf = createBufImage( width, height );			// backdrop and walls
    	background = backgroundBuf.createGraphics( );	
    	background.drawImage( bkdrop, 0, 0, width, height, this );
/*
 		backgroundBuf = createBufImage( width, height );			// backdrop and walls
    	background = backgroundBuf.createGraphics( );	
		background.setColor( Color.black );
		background.fillRect( 0,0, width, height );
    	background.setColor( Color.gray );
		for ( int i=0; i<walls.size( ); i++ )
		{
			Rectangle r = (Rectangle )walls.get( i );
			background.fillRect ( r.x, r.y, r.width, r.height );
		}
		*/
	}
    public void keyReleased( KeyEvent ke ) 
    { 
        player.stopMoving( );
    }
    /*  KeyListener methods */
    public void keyPressed( KeyEvent key )
    {
         int code = key.getKeyCode( );  
         if( code == KeyEvent.VK_UP || code == KeyEvent.VK_8 )
             player.moveUp( );
         else if( code == KeyEvent.VK_RIGHT )
             player.moveRight( );
         else if( code == KeyEvent.VK_LEFT )
             player.moveLeft( );
         else if( code == KeyEvent.VK_DOWN || code == KeyEvent.VK_2)
             player.moveDown( );
         if ( checkCollisionWalls( player.getDimensions( ) ))
        	 player.undoMove( );
     }    
    public void keyTyped( KeyEvent ke ) { }
    /* end KeyListener methods */
	public void paint( Graphics g )
	{
		g.drawImage( screenBuf,0,0,this);
	}
	public void update(Graphics g)
	{
		paint(g);
	}
	public void run( )
	{ 
		paintWalls(  );

		screenBuf = createBufImage( width, height );
		Graphics gapplet = (Graphics2D )screenBuf.getGraphics( );

	      while( true )
	      {
	    	  gapplet.drawImage( backgroundBuf, 0,0,  this );	// first draw background on buffer
	   		  if ( ! exit.isVisible( ) && checkCollisionFairy( ) )		// exit not yet visible, check if collision with fairy
	    			  exit.setVisible( true );
			  exit.paintComponent( gapplet );
			  moveFairy( );
	    	  fairy.paintComponent( gapplet );						// draw the fairy
	    	  player.paintComponent( gapplet );					// then draw player on buffer
	    	  if ( exit.isVisible( ) && player.getDimensions( ).intersects( exit.getDimensions( ) )  )
	    	  {
	    		  gapplet.setFont( new Font( "Serif", Font.BOLD, 42 ) );
	    		  gapplet.setColor( Color.WHITE );
	    		  gapplet.drawString( "YOU WIN!", 60, 120 );
	    	  }
	    	  repaint( );	// draw buffer to applet
	    	  try {    
	                    Thread.sleep(10);
                    } catch( Exception ex ) { stop( ); }
	      }
	}
	public void moveFairy( )
	{
		boolean badLocation = true;				// keep track of whether we found a good location or not
		int numTries = 10;								// give up after a while to prevent infinite loop
		while( badLocation && numTries > 0 )
		{
			int newx = random.nextInt( fairy.speed );		// generate a new random coodinate based on speed of fairy
			int newy = random.nextInt( fairy.speed );
			if ( random.nextInt( 2 ) == 0 )		// change direction in x
				newx = -1 * newx;
			if ( random.nextInt( 2 ) == 0 )
				newy = -1 * newy;
			fairy.setLocation(fairy.x + newx, fairy.y + newy);
			if ( checkCollisionWalls( fairy.getDimensions( ) ) )
				fairy.undoMove( );
			else
				badLocation = false;
			numTries = numTries -1;
		}
	}
}


Also include Sprite.java and Thing.java from other example.