Doubt Example

[Higor Zardo]

class Animal { public String noise() { return "peep"; } }
 
class Dog extends Cat { public String noise() { return "bark"; } }
 
class Cat extends Animal { public String noise() { return "meow"; } }
 
class TesteConver{
      public static void main(String [] args) {
             Animal animal = new Dog();
             Animal cat = (Cat)animal;
             System.out.println(cat.noise());
             System.out.println(animal.noise());
      }
 

 
}    

Why this code print "bark bark" and not "meow bark"?
I dont understand.

Thanks!

[Ben Souther]

Because you never created a cat object.

[Gaurav Joshi]

Always remember the actual object created, Dog in this example.At run time jvm will invoke the overrided method of actual object(Polymorphism)

Here Animal and Cat are the references

[Higor Zardo]

Thanks you friends!!!

[Higor Zardo]

Just more one doubt.
Reference variable always is modified and never the object or object can be modified too in some circustance?

[Higor Zardo]

Look,

public class TesteConver2{
             public final String FOO = "foo";
 
      public static void main(String [] args) {
             TesteConver2 b = new TesteConver2();
             Sub s = new Sub();
             System.out.print(b.FOO);
             System.out.print(s.FOO); 
             System.out.print(((TesteConver2)s).FOO);
      }
 

 
}
 
class Sub extends TesteConver2 { public final String FOO = "bar"; }

The output of this code is: foobarfoo
But the object in "((TesteConver2)s).FOO" is not Sub? then i think that Sub should be call because polymorphism. not?

Thanks to help me.

[sridhar row]

Polymorphic invocation works only for overridden instance methods not variables

[Higor Zardo]

sridhar row,
thank you very much!!!