Considere a execução dos códigos Java...

S1.java

abstract class S1 {

protected int x;

protected int y;

public void mostra(){

System.out.print("Prova");

}

}

S2.java

public class S2 extends S1{

int y;

public void mostra(){

super.y=10;

System.out.println("x=" +(++x)+" e "+"y= "+(y+x));

}

public static void main(String args[]){

S2 s;

s=new S2();

s.x=10;

s.y=6;

s.mostra();

}

}