Using instanceof in if statement

Question

if(objectName instanceof Mammal currentMammal){
    currentMammal.shedHair();

if the (objectName instanceof Mammal) is true then currentMammal is casted to Mammal. I see this works, but dont know how. I have never seen this stuff going on in "if" statements

I believe this makes sense.

if (ao instanceof Mammal) {
    Mammal currentMammal = (Mammal) ao;
    currentMammal.shedHair();
}

but this first snippet is over my head

Answer 1

Got the answer. https://docs.oracle.com/en/java/javase/17/language/pattern-matching-instanceof-operator.html#GUID-843060B5-240C-4F47-A7B0-95C42E5B08A7.

This is a new feature added in JDK 16.

Answer 2

The first one is just a syntactic sugar. Actually it do the Mammal currentMammal = (Mammal) ao; for you.