Questions and Exercises
Trail: Learning the Java Language
Lesson: Annotations

Questions and Exercises: Annotations


  1. What is wrong with the following interface?

    public interface House {
        void open();
        void openFrontDoor();
        void openBackDoor();
  2. 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 produces a warning because open was deprecated (in the interface). What can you do to get rid of that warning?

  3. Will the following code compile without error? Why or why not?

    public @interface Meal { ... }
    @Meal("breakfast", mainDish="cereal")
    @Meal("lunch", mainDish="pizza")
    @Meal("dinner", mainDish="salad")
    public void evaluateDiet() { ... }


  1. Define an annotation type for an enhancement request with elements id, synopsis, engineer, and date. Specify the default value as unassigned for engineer and unknown for date.

Check your answers.

Previous page: Repeating Annotations
Next page: Interfaces and Inheritance