What is a NullPointerException, and how do I fix it?

Question

Can anyone help me what is null pointer exception? And why it occurs?

Answer 1

Basically, NullPointerException is a runtime exception and it occurs whenever an object reference has a null value. Below is an example :

Input:

public class Intellipaat {

   public static void main(String[] args) {

      Object ref = null;

      ref.toString(); // this will throw a NullPointerException

   }

} 

Output:

Exception in thread "main" java.lang.NullPointerException

at Tester.main(Tester.java:4)

I hope this will help.

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