>537

class A {
public void proc(iDisp d) {
d.show();
}
}

class Program {
public static void main(String args[]) {
A a = new A();
B b = new B();
a.proc(b);
}
}

interface iDisp {
void show();
}

class B implements iDisp {
public void show() {
System.out.println( "Bクラスです" );
}
}