Questions and Exercises: Annotations

Questions
1. What is wrong with the following interface?
public interface House {
@Deprecated
void open();
void openFrontDoor();
void openBackDoor();
}

2. Compile this program:
interface Closable {
void close();
}

class File implements Closable {
@Override
public void close() {
//... close this file...
}
}

What happens? Can you explain why?
3. Consider this implementation of the House interface, shown in Question 1.

public class MyHouse implements House {
public void open() {}
public void openFrontDoor() {}
public void openBackDoor() {}
}

If you compile this program, the compiler complains that open has been deprecated (in the interface). What can you do to get rid of that warning