rishi
khiladi1@hotmail.com

what does this error message mean??

java.lang.NullPointerException
     java.lang.Throwable()
     java.lang.Exception()
     java.lang.RuntimeException()
     java.lang.NullPointerException()
     void uvm.awt.UvmGraphics.setXORMode(java.awt.Color)
     void ball.coin(java.awt.Graphics)
     void bouncing_ball.start()
     void sun.applet.AppletPanel.run()
     void java.lang.Thread.run()
     void java.lang.Thread.start()

miraculously, You have tried to reference an object with a null value...most likely you defined an object(object variable_ref ), but didn't initialize it (variable_ref = new object ) Also look for any variables that were initialized to 'null'...

8-10-98
Shari McGuirl
mcguirsl@muss.cis.mcmaster.ca

It means that you are trying to invoke a method on a variable that has no value. You should go though and see which variable or method that it is refering to and either set up an initial value for it or see where you have set its value to null.