Polymorphism

AP Computer Science A· difficulty 3/5

public class A {
    public String show() { return "A"; }
}
public class B extends A {
    public String show() { return "B"; }
}
public static String pick(A x) { return x.show(); }
System.out.println(pick(new B()));

What is printed?

A
$AB$
B
$Compile-time error$
C
$B$
check_circle
D
$A$

Explanation

Even though the parameter is declared as A, the actual object is B; dynamic dispatch calls B.show().

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