What is the 'instanceof' operator used for in Java?

Question

What is the instanceof operator used for? I\'ve seen stuff like

if (source instanceof Button) {
    //...
} else {
    //...
}

Answer 1

Can be used as a shorthand in equality check.

So this code

if(ob != null && this.getClass() == ob.getClass) {
}

can be written as

if(ob instanceOf ClassA) {
}