package p;
abstract class A<T>{
public abstract void f();
public abstract T m(T t);
}
abstract class B extends A<String>{
@Override
public String m(String t) {
String s= t;
return null;
}
public abstract void f();
}
class C extends A<Object>{
public void f(){}
@Override
public Object m(Object t) {
Object s= t;
return null;
}
}