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Questions and Exercises: Interfaces

Questions

1. What methods would a class that implements thejava.lang.CharSequence interface have to implement?
2. What is wrong with the following interface?

   public interface SomethingIsWrong {    void aMethod(int aValue){        System.out.println("Hi Mom");    }}

3. Fix the interface in question 2.
4. Is the following interface valid?

   public interface Marker {}

Exercises

1. Write a class that implements theCharSequence interface found in thejava.lang package. Your implementation should return the string backwards. Select one of the sentences from this book to use as the data. Write a smallmain method to test your class; make sure to call all four methods.
2. Suppose you have written a time server that periodically notifies its clients of the current date and time. Write an interface the server could use to enforce a particular protocol on its clients.

Check your answers.