A-A show(A) accepts B (upcast). Calls A.show(A) returning "A-A".

Polymorphism

AP Computer Science A· difficulty 4/5

public class A {
    public String show(A o) { return "A-A"; }
}
public class B extends A { }
A x = new A();
B y = new B();
System.out.println(x.show(y));

What is printed?

A
$B-A$
B
$Compile-time error$
C
$B-B$
D
$A-A$
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Explanation

show(A) accepts B (upcast). Calls A.show(A) returning "A-A".

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