Thread: java.lang.NullPointerException - Help

Im trying to run this code i have written but cannot see whats wrong with it. i get the java.lang.NullPointerException error when running it.

Basically what im trying to do is to move a background x position by using a new method i have created in Dice class (moveBackground).

The code i am running is

di.moveBackground(); where di is the object name

can any one help as i havent got a clue as im new to java

Class Called Dice only part of code is pasted here

private Square background;
 
 public Square getBackground()
   {
      return background;
   }
 
  public void moveBackground()    /** this is what method i am trying to run */
     {
        background.setXPos(75);
      }

Square class

 public void setXPos(int x)
   {
      this.xPos = x;
      this.update();
   }

Thanks in advance

Is the background variable instantiated prior to calling moveBackground, for example in the constructor or using a setter?

You never set or create the background variable. Look at the constructor of the class Dice, there should be something like
background = bg;
or
background = new Square();

Originally Posted by copeg

You never set or create the background variable. Look at the constructor of the class Dice, there should be something like
background = bg;
or
background = new Square();

brilliant. thanks very much for this

Really appreciate it