What would cause this error???

[jason candelora]

java.lang.NullPointerException
at shapeDriver.main(shapeDriver.java:13)
Exception in thread "main"

[Avi Abrami]

Hi Jason,
You have a null pointer at line 13 in file "shapeDriver.java" (or is this a 'trick' question :-)
Perhaps if you posted (at least) line 13 of file "shapeDriver.java", I may be able to offer more.
Good Luck,
Avi.

[David Crossett]

Without any code, the best guess would be that you are using a variable or class instance without instantiating it. That's usually what causes my 'nullpointer exception' errors....how bout some more code?

[Dirk Schreckmann]

What would cause this error???
This would cause it.

public class Foo
{
  private static Foo bar = null;
  
  private void method()
  {
    
  }
  
  public static void main(String[] args)
  {
    bar.method();  // NullPointerException here
  }
}

So would this.

public class Foo
{
  private static Foo bar;
  
  private void method()
  {
    
  }
  
  public static void main(String[] args)
  {
    bar.method();  // NullPointerException here
  }
}

[jason candelora]

Thanks a lot..it was the problem using a variable that was not instantiated..
Jason