Return type of the overload method (new feature of JDK50)

Public class AgedP {

Public Object getSSS (){
System. out. println ("return Obj ");
Return null;
}

}

Public class Kinder extends AgedP {

Public String getSSS (){
System. out. println ("return String ");
Return "";
}

Public static void main (String [] args ){
Kinder kinder = new Kinder ();
Kinder. getSSS ();
AgedP kinder2 = new Kinder ();
Kinder2.getSSS ();
AgedP agedP = new AgedP ();
AgedP. getSSS ();
}

}

This code is compiled in the JDK1.5 environment and output after running:

Return String
Return String
Return Obj

Compilation errors occur in the JDK1.4 environment.

Conclusion:

In JDK1.5, the return type of the overload method in the subclass can be the subclass of the return type of the overload method.