Why it throws null pointer exception when object is initialized to null and then trying to access class method?

Question

public class Abc
{
   public static void main(String args[])
   {
      def obj=null;
      obj.method();
    }
}
class Def
{
   void method()
   {
       System.out.println("class def->>> method()");
   }
}

The output of this code is generating a NullPointerException and why?

Answer 1

The NullPointerException means you tried to deference a null value so you get the expected behaviour.

It doesn't have anything to do with detecting uninitialised values. It's not called UninitialisedException