03 November 2013

Unboxing NPE in Java

It is very famous error, and you can find it in google very easy.

I am just trying to duplicating it here...

import java.util.List;
import java.util.ArrayList;

public class Unboxing{
    public static void main(String[] args){
        List<Integer> list = new ArrayList();
        list.add(getInteger());
        int x = list.get(0);
        System.out.printf("x value is %i\n", x);
    }

    private static Integer getInteger(){
        return null;
    }
}


And here's the result

$ java Unboxing 
Exception in thread "main" java.lang.NullPointerException
    at Unboxing.main(Unboxing.java:8)

That's all folks.
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