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Java Java Data Structures - Retired Getting There Type Casting

juan esquivel
juan esquivel
1,190 Points
Posted by juan esquivel
juan esquivel
1,190 Points

please help.. i don't understand type casting .. I've watch over and over but it just doesn't click

what is type casting and were can i learn more "type casting in java"

1 Answer

João Elvas
João Elvas
5,400 Points
João Elvas
João Elvas
5,400 Points

Hello buddy,

It is really simple, don't worry.

As you should know by now, Java is an object oriented language, so guess what?! Everything is an object!

That means every object inherits from the class Object, so a String is an object, Integer is an object, your class instances are objects.

Now a bit of code:

class Animal{

    public void walk(){
    // doesn't matter
    }

}

class Cat extends Animal{
    @Override
    public void walk(){
    // doesn't matter
    }

    public void jump(){   // cats jump a lot :p
    // doesn't matter
    }
}

Now using those classes... without cast.

    Animal a = new Cat();

    a.speak(); // we are making speak on an Animal and that is impossible so we get: Compile Error

And now lets use cast

    Animal a = new Cat();

    Cat b = (Cat) a
    b.speak(); // Now we are doing it on a cat as we made sure b is a Cat so there will be the speak method.

Good luck!