Auto unboxing pitfall

Lets try a simple code snippet to see how unboxing of null works.


public class TestAutoBoxingUnboxing {
     public static void main(String[] args) {
         Integer a = null, b = null;
         int iAmA = a;
         int iAmB = b;

         //Will this print???
         System.out.println("Lets see the primitive ints " + iAmA + " and " + iAmB);
     }
}


Running the code produces:
Exception in thread "main" java.lang.NullPointerException at TestAutoBoxingUnboxing.main(TestAutoBoxingUnboxing.java:17)


Moral:

Cannot unbox null, it will throw a NullPointerException. So we have to be more careful with primitives than before to avoid such problems.