The Terrible Dangers of Autoboxing (Part 2)

Solution to part 1:

j is equal to m
j is equal to K
K is equal to m

The result of one of the Object being null, will of course cause a NullPointerException.

Part 2:

class Autoboxing
{ 

    public static void main(String[] args)
    {
        Integer a = 10;
        Integer b = 10;
        Integer c = 1000;
        Integer d = 1000;
        System.out.println(a == b); //true
        System.out.println(c == d); //false
    }

};

Please explain.

(Found it in my Linkedin groups "Sun Certified Java Programmer" here)

References

Most common gotchas in Java

http://vanillajava.blogspot.nl/2014/02/most-common-gotchas-in-java.html