How to use null in switch

Question

Integer i = ...

switch (i){
    case null:
        doSomething0();
        break;    
    }

In the code above I cant use null in switch case state

Answer 1

This is not possible with a switch statement in Java. Check for null before the switch:

if (i == null) {
    doSomething0();
} else {
    switch (i) {
    case 1:
        // ...
        break;
    }
}

You can't use arbitrary objects in switch statements^*. The reason that the compiler doesn't complain about switch (i) where i is an Integer is because Java auto-unboxes the Integer to an int. As assylias already said, the unboxing will throw a NullPointerException when i is null.

^* Since Java 7 you can use String in switch statements.

More about switch (including example with null variable) in Oracle Docs - Switch