OnJava8-Examples/reusing/FinalOverridingIllusion.java
2015-04-20 15:36:01 -07:00

50 lines
1.1 KiB
Java

//: reusing/FinalOverridingIllusion.java
// It only looks like you can override
// a private or private final method.
import static net.mindview.util.Print.*;
class WithFinals {
// Identical to "private" alone:
private final void f() { print("WithFinals.f()"); }
// Also automatically "final":
private void g() { print("WithFinals.g()"); }
}
class OverridingPrivate extends WithFinals {
private final void f() {
print("OverridingPrivate.f()");
}
private void g() {
print("OverridingPrivate.g()");
}
}
class OverridingPrivate2 extends OverridingPrivate {
public final void f() {
print("OverridingPrivate2.f()");
}
public void g() {
print("OverridingPrivate2.g()");
}
}
public class FinalOverridingIllusion {
public static void main(String[] args) {
OverridingPrivate2 op2 = new OverridingPrivate2();
op2.f();
op2.g();
// You can upcast:
OverridingPrivate op = op2;
// But you can't call the methods:
//! op.f();
//! op.g();
// Same here:
WithFinals wf = op2;
//! wf.f();
//! wf.g();
}
} /* Output:
OverridingPrivate2.f()
OverridingPrivate2.g()
*///:~