Can't find the bug with NullPointerExce ption.......... ......

[Smith]

The program compiled successfully,
but it gives the following error on runtime....

java.lang.NullP ointerException
at FrogManiaApp.pa int(FrogManiaAp p.java:102)
at sun.awt.Repaint Area.paint(Repa intArea.java:17 7)
at
sun.awt.windows .WComponentPeer .handleEvent(WC omponentPeer.ja va:260)
at java.awt.Compon ent.dispatchEve ntImpl(Componen t.java:3678)
at java.awt.Contai ner.dispatchEve ntImpl(Containe r.java:1627)
at java.awt.Compon ent.dispatchEve nt(Component.ja va:3477)
at java.awt.EventQ ueue.dispatchEv ent(EventQueue. java:456)
at
java.awt.EventD ispatchThread.p umpOneEventForH ierarchy(EventD ispatchTh
read.java:201)
at
java.awt.EventD ispatchThread.p umpEventsForHie rarchy(EventDis patchThre
ad.java:151)
at
java.awt.EventD ispatchThread.p umpEvents(Event DispatchThread. java:145)

at
java.awt.EventD ispatchThread.p umpEvents(Event DispatchThread. java:137)

at java.awt.EventD ispatchThread.r un(EventDispatc hThread.java:10 0)
java.lang.NullP ointerException
at FrogManiaApp.pa int(FrogManiaAp p.java:102)
at sun.awt.Repaint Area.paint(Repa intArea.java:17 7)
at
sun.awt.windows .WComponentPeer .handleEvent(WC omponentPeer.ja va:260)
at java.awt.Compon ent.dispatchEve ntImpl(Componen t.java:3678)
at java.awt.Contai ner.dispatchEve ntImpl(Containe r.java:1627)



And the program source is as below.....


import javax.swing.JOp tionPane;
import java.applet.App let;
import java.awt.*;
import java.awt.event. *;

public class FrogManiaApp extends Applet implements MouseListener
{
private static final int IMG_FROG_N=0;
private static final int IMG_FROG_E=1;
private static final int IMG_FROG_S=2;
private static final int IMG_FROG_W=3;
private static final int IMG_DRAGONFLY=4 ;
private static final int IMG_LEAF=5;
private static final int NUM_OF_IMG=6;
private static final long SLEEP_TIME=200;
private static final int STATUS_HEIGHT=2 0;

private Image[] images=new Image[6];
private Point tconvert=new Point();
private String configFile;

private int tnotice;

private FrogMania game;
private Dimension imageSize;
private Point input;
private FrogManiaRunner runner;
private Point highlightPoint;
private Image buffer;
private Graphics bufferG;
private boolean buffered;
private Pond pond;

private Color color;

private MediaTracker tracker;

public void init()
{
tracker=new MediaTracker(th is);
color=new Color(0,0,0);

for(int i=0; i<=5; i++)
{
images[i]=getImage(getCo deBase(),"img"+ i+".gif");
tracker.addImag e(images[i],0);
try
{ tracker.waitFor All(); }
catch (InterruptedExc eption ex)
{ System.out.prin tln("Interrupte d when reading image files. ...><..."); }
}

imageSize=new
Dimension(image s[0].getWidth(this) ,images[0].getHeight(this ));

configFile=getP arameter("confi g");
if (configFile==nu ll)
{ configFile="con fig01.dat"; }

pond=new Pond(getDocumen tBase(),configF ile);
game=new FrogMania(pond, this);

buffered=false;
highlightPoint= null;
addMouseListene r(this);
}

public void update(Graphics g)
{
paint(g);
}

public void paint(Graphics g)
{
if (!buffered)
{
buffer=createIm age(420,370);
bufferG=buffer. getGraphics();
buffered=true;
}

for (int y=0; y<=5; y++)
{
for (int x=0; x<=4; x++)
{
tconvert=new Point(x,y);

if (game.getPond() .getAnimal(tcon vert)==null)
{
bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);
}
else
if (game.getPond() .getAnimal(tcon vert) instanceof Frog)
{
if
(((Frog)(pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.NORTH ))
{ tnotice=IMG_FRO G_N; }
if
((((Frog)pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.SOUTH ))
{ tnotice=IMG_FRO G_S; }
if
((((Frog)pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.WEST) )
{ tnotice=IMG_FRO G_W; }
if
((((Frog)pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.EAST) )
{ tnotice=IMG_FRO G_E; }
bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

bufferG.drawIma ge(images[tnotice],y*imageSize.wi dth,x*imageSize .height,this);
}
else
if (pond.getAnimal (tconvert) instanceof Dragonfly)
{

bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

bufferG.drawIma ge(images[IMG_DRAGONFLY],y*imageSize.wi dth,x*imageSize .height,this);
}
}
}

if (highlightPoint !=null)
{
bufferG.setColo r(Color.red);

bufferG.drawRec t((int)highligh tPoint.getX(),( int)highlightPo int.getY(),imag eSize.width,ima geSize.height);
bufferG.setColo r(Color.black);

bufferG.fillRec t(0,5*imageSize .height,6*image Size.width,5*im ageSize.height+ STATUS_HEIGHT);
bufferG.setColo r(Color.green);
bufferG.drawStr ing("Number of dragonflies:
"+game.getPond( ).numOfDragonfl ies(),(int)(ima geSize.width/3.5),(int)(5*im ageSize.height+ STATUS_HEIGHT/4));
}

g.drawImage(buf fer, 0, 0, this);
}

public void updateDisplay()
{
repaint();
}

public void highlight(Point pt)
{
this.highlightP oint=new Point((int)pt.g etX(),(int)pt.g etY());
try
{ Thread.sleep(SL EEP_TIME); }
catch (InterruptedExc eption ex)
{ }
}

public void start()
{
runner=new FrogManiaRunner (game);
runner.start();
}

public synchronized void stop()
{
game = null;
runner = null;
input = null;
notifyAll();
}

public void gameOver()
{

JOptionPane.sho wMessageDialog( null,"informati on","informatio n",JOptionPane. INFORMATION_MES SAGE);
}

public synchronized Point getInput()
{
try
{ wait(); }
catch (InterruptedExc eption ex)
{ }

return input;
}

public synchronized void mouseClicked(Mo useEvent e)
{
input=e.getPoin t();
notifyAll();
}

public synchronized void mouseExited(Mou seEvent e)
{ }

public synchronized void mousePressed(Mo useEvent e)
{ }

public synchronized void mouseReleased(M ouseEvent e)
{ }

public synchronized void mouseEntered(Mo useEvent e)
{ }
}

Where is it?!?

A billion thx for your responses!!!!

[Martin Froment]

It will be more easier if you tell us where's your line 102...
Are you sure that your "getOrientation ()" method is never returning null ?

"Smith" <fo****@hotmail .com> wrote in message
news:41******** **@rain.i-cable.com...

The program compiled successfully,
but it gives the following error on runtime....

java.lang.NullP ointerException
at FrogManiaApp.pa int(FrogManiaAp p.java:102)
at sun.awt.Repaint Area.paint(Repa intArea.java:17 7)
at
sun.awt.windows .WComponentPeer .handleEvent(WC omponentPeer.ja va:260)
at java.awt.Compon ent.dispatchEve ntImpl(Componen t.java:3678)
at java.awt.Contai ner.dispatchEve ntImpl(Containe r.java:1627)
at java.awt.Compon ent.dispatchEve nt(Component.ja va:3477)
at java.awt.EventQ ueue.dispatchEv ent(EventQueue. java:456)
at
java.awt.EventD ispatchThread.p umpOneEventForH ierarchy(EventD ispatchTh
read.java:201)
at
java.awt.EventD ispatchThread.p umpEventsForHie rarchy(EventDis patchThre
ad.java:151)
at
java.awt.EventD ispatchThread.p umpEvents(Event DispatchThread. java:145)

at
java.awt.EventD ispatchThread.p umpEvents(Event DispatchThread. java:137)

at java.awt.EventD ispatchThread.r un(EventDispatc hThread.java:10 0)
java.lang.NullP ointerException
at FrogManiaApp.pa int(FrogManiaAp p.java:102)
at sun.awt.Repaint Area.paint(Repa intArea.java:17 7)
at
sun.awt.windows .WComponentPeer .handleEvent(WC omponentPeer.ja va:260)
at java.awt.Compon ent.dispatchEve ntImpl(Componen t.java:3678)
at java.awt.Contai ner.dispatchEve ntImpl(Containe r.java:1627)



And the program source is as below.....


import javax.swing.JOp tionPane;
import java.applet.App let;
import java.awt.*;
import java.awt.event. *;

public class FrogManiaApp extends Applet implements MouseListener
{
private static final int IMG_FROG_N=0;
private static final int IMG_FROG_E=1;
private static final int IMG_FROG_S=2;
private static final int IMG_FROG_W=3;
private static final int IMG_DRAGONFLY=4 ;
private static final int IMG_LEAF=5;
private static final int NUM_OF_IMG=6;
private static final long SLEEP_TIME=200;
private static final int STATUS_HEIGHT=2 0;

private Image[] images=new Image[6];
private Point tconvert=new Point();
private String configFile;

private int tnotice;

private FrogMania game;
private Dimension imageSize;
private Point input;
private FrogManiaRunner runner;
private Point highlightPoint;
private Image buffer;
private Graphics bufferG;
private boolean buffered;
private Pond pond;

private Color color;

private MediaTracker tracker;

public void init()
{
tracker=new MediaTracker(th is);
color=new Color(0,0,0);

for(int i=0; i<=5; i++)
{
images[i]=getImage(getCo deBase(),"img"+ i+".gif");
tracker.addImag e(images[i],0);
try
{ tracker.waitFor All(); }
catch (InterruptedExc eption ex)
{ System.out.prin tln("Interrupte d when reading image files. ...><..."); }
}

imageSize=new
Dimension(image s[0].getWidth(this) ,images[0].getHeight(this ));

configFile=getP arameter("confi g");
if (configFile==nu ll)
{ configFile="con fig01.dat"; }

pond=new Pond(getDocumen tBase(),configF ile);
game=new FrogMania(pond, this);

buffered=false;
highlightPoint= null;
addMouseListene r(this);
}

public void update(Graphics g)
{
paint(g);
}

public void paint(Graphics g)
{
if (!buffered)
{
buffer=createIm age(420,370);
bufferG=buffer. getGraphics();
buffered=true;
}

for (int y=0; y<=5; y++)
{
for (int x=0; x<=4; x++)
{
tconvert=new Point(x,y);

if (game.getPond() .getAnimal(tcon vert)==null)
{
bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);
}
else
if (game.getPond() .getAnimal(tcon vert) instanceof Frog)
{
if
(((Frog)(pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.NORTH ))
{ tnotice=IMG_FRO G_N; }
if
((((Frog)pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.SOUTH ))
{ tnotice=IMG_FRO G_S; }
if
((((Frog)pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.WEST) )
{ tnotice=IMG_FRO G_W; }
if
((((Frog)pond.g etAnimal(tconve rt))).getOrient ation().equals( Direction.EAST) )
{ tnotice=IMG_FRO G_E; }
bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

bufferG.drawIma ge(images[tnotice],y*imageSize.wi dth,x*imageSize .height,this);
}
else
if (pond.getAnimal (tconvert) instanceof Dragonfly)
{

bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

bufferG.drawIma ge(images[IMG_DRAGONFLY],y*imageSize.wi dth,x*imageSize .height,this);
}
}
}

if (highlightPoint !=null)
{
bufferG.setColo r(Color.red);

bufferG.drawRec t((int)highligh tPoint.getX(),( int)highlightPo int.getY(),imag eSize.width,ima geSize.height);
bufferG.setColo r(Color.black);

bufferG.fillRec t(0,5*imageSize .height,6*image Size.width,5*im ageSize.height+ STATUS_HEIGHT);
bufferG.setColo r(Color.green);
bufferG.drawStr ing("Number of dragonflies:
"+game.getPond( ).numOfDragonfl ies(),(int)(ima geSize.width/3.5),(int)(5*im ageSize.height+ STATUS_HEIGHT/4));
}

g.drawImage(buf fer, 0, 0, this);
}

public void updateDisplay()
{
repaint();
}

public void highlight(Point pt)
{
this.highlightP oint=new Point((int)pt.g etX(),(int)pt.g etY());
try
{ Thread.sleep(SL EEP_TIME); }
catch (InterruptedExc eption ex)
{ }
}

public void start()
{
runner=new FrogManiaRunner (game);
runner.start();
}

public synchronized void stop()
{
game = null;
runner = null;
input = null;
notifyAll();
}

public void gameOver()
{

JOptionPane.sho wMessageDialog( null,"informati on","informatio n",JOptionPane. INFORMATION_MES SAGE);
}

public synchronized Point getInput()
{
try
{ wait(); }
catch (InterruptedExc eption ex)
{ }

return input;
}

public synchronized void mouseClicked(Mo useEvent e)
{ input=e.getPoin t();
notifyAll();
}

public synchronized void mouseExited(Mou seEvent e)
{ }

public synchronized void mousePressed(Mo useEvent e)
{ }

public synchronized void mouseReleased(M ouseEvent e)
{ }

public synchronized void mouseEntered(Mo useEvent e)
{ }
}

Where is it?!?

A billion thx for your responses!!!!

[Roman Levandovsky]

Martin Froment wrote:

It will be more easier if you tell us where's your line 102...
Are you sure that your "getOrientation ()" method is never returning null ?

"Smith" <fo****@hotmail .com> wrote in message
news:41******** **@rain.i-cable.com...

The program compiled successfully,
but it gives the following error on runtime....

java.lang.Nul lPointerExcepti on
at FrogManiaApp.pa int(FrogManiaAp p.java:102)
at sun.awt.Repaint Area.paint(Repa intArea.java:17 7)
at
sun.awt.windo ws.WComponentPe er.handleEvent( WComponentPeer. java:260)
at java.awt.Compon ent.dispatchEve ntImpl(Componen t.java:3678)
at java.awt.Contai ner.dispatchEve ntImpl(Containe r.java:1627)
at java.awt.Compon ent.dispatchEve nt(Component.ja va:3477)
at java.awt.EventQ ueue.dispatchEv ent(EventQueue. java:456)
at
java.awt.Even tDispatchThread .pumpOneEventFo rHierarchy(Even tDispatchTh
read.java:201 )
at
java.awt.Even tDispatchThread .pumpEventsForH ierarchy(EventD ispatchThre
ad.java:151 )
at
java.awt.Even tDispatchThread .pumpEvents(Eve ntDispatchThrea d.java:145)

at
java.awt.Even tDispatchThread .pumpEvents(Eve ntDispatchThrea d.java:137)

at java.awt.EventD ispatchThread.r un(EventDispatc hThread.java:10 0)
java.lang.Nul lPointerExcepti on
at FrogManiaApp.pa int(FrogManiaAp p.java:102)
at sun.awt.Repaint Area.paint(Repa intArea.java:17 7)
at
sun.awt.windo ws.WComponentPe er.handleEvent( WComponentPeer. java:260)
at java.awt.Compon ent.dispatchEve ntImpl(Componen t.java:3678)
at java.awt.Contai ner.dispatchEve ntImpl(Containe r.java:1627)



And the program source is as below.....


import javax.swing.JOp tionPane;
import java.applet.App let;
import java.awt.*;
import java.awt.event. *;

public class FrogManiaApp extends Applet implements MouseListener
{
private static final int IMG_FROG_N=0;
private static final int IMG_FROG_E=1;
private static final int IMG_FROG_S=2;
private static final int IMG_FROG_W=3;
private static final int IMG_DRAGONFLY=4 ;
private static final int IMG_LEAF=5;
private static final int NUM_OF_IMG=6;
private static final long SLEEP_TIME=200;
private static final int STATUS_HEIGHT=2 0;

private Image[] images=new Image[6];
private Point tconvert=new Point();
private String configFile;

private int tnotice;

private FrogMania game;
private Dimension imageSize;
private Point input;
private FrogManiaRunner runner;
private Point highlightPoint;
private Image buffer;
private Graphics bufferG;
private boolean buffered;
private Pond pond;

private Color color;

private MediaTracker tracker;

public void init()
{
tracker=new MediaTracker(th is);
color=new Color(0,0,0);

for(int i=0; i<=5; i++)
{
images[i]=getImage(getCo deBase(),"img"+ i+".gif");
tracker.addIm age(images[i],0);
try
{ tracker.waitFor All(); }
catch (InterruptedExc eption ex)
{ System.out.prin tln("Interrupte d when reading image files. ...><..."); }
}

imageSize=n ew
Dimension(ima ges[0].getWidth(this) ,images[0].getHeight(this ));

configFile=ge tParameter("con fig");
if (configFile==nu ll)
{ configFile="con fig01.dat"; }

pond=new Pond(getDocumen tBase(),configF ile);
game=new FrogMania(pond, this);

buffered=fals e;
highlightPoin t=null;
addMouseListe ner(this);
}

public void update(Graphics g)
{
paint(g);
}

public void paint(Graphics g)
{
if (!buffered)
{
buffer=create Image(420,370);
bufferG=buffe r.getGraphics() ;
buffered=true ;
}

for (int y=0; y<=5; y++)
{
for (int x=0; x<=4; x++)
{
tconvert=ne w Point(x,y);

if (game.getPond() .getAnimal(tcon vert)==null)
{
bufferG.drawI mage(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);
}
else
if (game.getPond() .getAnimal(tcon vert) instanceof Frog)
{
if
(((Frog)(pond .getAnimal(tcon vert))).getOrie ntation().equal s(Direction.NOR TH))
{ tnotice=IMG_FRO G_N; }
if
((((Frog)pond .getAnimal(tcon vert))).getOrie ntation().equal s(Direction.SOU TH))
{ tnotice=IMG_FRO G_S; }
if
((((Frog)pond .getAnimal(tcon vert))).getOrie ntation().equal s(Direction.WES T))
{ tnotice=IMG_FRO G_W; }
if
((((Frog)pond .getAnimal(tcon vert))).getOrie ntation().equal s(Direction.EAS T))
{ tnotice=IMG_FRO G_E; }
bufferG.drawI mage(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

bufferG.drawI mage(images[tnotice],y*imageSize.wi dth,x*imageSize .height,this);
}
else
if (pond.getAnimal (tconvert) instanceof Dragonfly)
{

bufferG.drawI mage(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

bufferG.drawI mage(images[IMG_DRAGONFLY],y*imageSize.wi dth,x*imageSize .height,this);
}
}
}

if (highlightPoint !=null)
{
bufferG.setCo lor(Color.red);

bufferG.drawR ect((int)highli ghtPoint.getX() ,(int)highlight Point.getY(),im ageSize.width,i mageSize.height );
bufferG.setCo lor(Color.black );

bufferG.fillR ect(0,5*imageSi ze.height,6*ima geSize.width,5* imageSize.heigh t+STATUS_HEIGHT );
bufferG.setCo lor(Color.green );
bufferG.drawS tring("Number of dragonflies:
"+game.getPon d().numOfDragon flies(),(int)(i mageSize.width/3.5),(int)(5*im ageSize.height+ STATUS_HEIGHT/4));
}

g.drawImage(b uffer, 0, 0, this);
}

public void updateDisplay()
{
repaint();
}

public void highlight(Point pt)
{
this.highligh tPoint=new Point((int)pt.g etX(),(int)pt.g etY());
try
{ Thread.sleep(SL EEP_TIME); }
catch (InterruptedExc eption ex)
{ }
}

public void start()
{
runner=new FrogManiaRunner (game);
runner.start( );
}

public synchronized void stop()
{
game = null;
runner = null;
input = null;
notifyAll() ;
}

public void gameOver()
{

JOptionPane.s howMessageDialo g(null,"informa tion","informat ion",JOptionPan e.INFORMATION_M ESSAGE);
}

public synchronized Point getInput()
{
try
{ wait(); }
catch (InterruptedExc eption ex)
{ }

return input;
}

public synchronized void mouseClicked(Mo useEvent e)
{ input=e.getPoin t();
notifyAll() ;
}

public synchronized void mouseExited(Mou seEvent e)
{ }

public synchronized void mousePressed(Mo useEvent e)
{ }

public synchronized void mouseReleased(M ouseEvent e)
{ }

public synchronized void mouseEntered(Mo useEvent e)
{ }
}

Where is it?!?

A billion thx for your responses!!!!

I suspect that your images[] array does not contain an image, thus when
you call >
bufferG.drawIma ge(images[IMG_LEAF],y*imageSize.wi dth,x*imageSize .height,this);

there is a null in images[IMG_LEAF] I could be wrong.
is that line 102? Since it is hard to figure out what line is 102 could
you paste that line in your reply?

Roman.