finaloverrideex.java

来自「JAVA编程思想第四版英文原版习题答案. pdf原版的」· Java 代码 · 共 34 行

// reusing/FinalOverrideEx.java
// TIJ4 Chapter Reusing, Exercise 21, page 269
/* Create a class with a final method. Inherit from that class and attempt to 
* override that method.
*/
import static net.mindview.util.Print.*;

class WithFinal {
	final void f() { print("WithFinal.f()"); }
	void g() { print("WithFinal.g()"); }
	final void h() { print("WitFinal.h()"); }
} 

class OverrideFinal extends WithFinal {
	// attempt to override:
	// public final void f() { print("OverrideFinal.f()"); } // no can do
	@Override public void g() { print("OverrideFinal.g()"); } // OK, not final
	// final void h(); { print("OVerrideFinal.h()"); } // cannot override final 	
}

public class FinalOverrideEx {
	public static void main(String[] args) {
		OverrideFinal of = new OverrideFinal();
		of.f();
		of.g();
		of.h();
		// Upcast:
		WithFinal wf = of;
		wf.f(); 
		wf.g();
		wf.h(); 
	}
}