Java Questions 31 - 40  «Prev  Next»

Overloading vs. Overriding

  1. Do you have to pay attention to the return type when overloading a method?

    No. When you overload a method (by changing the parameters), the return type does not have to match that of the superclass version.

  2. What is the difference between arguments and parameters?

    Parameters are the elements in the methods signature that indicate what the method must receive when its inovked.

  3. Which characteristics must an overriding method in a subclass contain?

    When a subclass wants to override an inherited method the subclass must define a method that matches the inherited version exactly (For reference types covariant returns are allowed).

  4. What is a covariant return type?

    As of Java 5, you are allowed to change the return type in the overriding method as long as the new return type is a subtype of the declared return type of the overridden method.

  5. What role does the return type play with regards to overloading and overriding?

    Know the following 2 facts:
    1. Overloaded methods can change the return type
    2. overriding methods can change the return type if the overridden method is a subclass of the Superclass.

    Covariant Return Type

  6. For primitive return types, what must be true of the overriding method?

    When overriding a method, the method in the subclass must match the inherited version exactly.

  7. What task must be completed to create a new object?

    You can not make a new object without invoking a constructor.

  8. How are objects initialized?

    Constructors are the code that runs whenever you use the keyword new.
    Initialization: The new operator is followed by a call to a constructor, which initializes the new object.

  9. What must every class possess?

    Every class, including abstract class, must have a constructor.

  10. What are two key points to remember about constructors?

    1. Constructors do not have a return type
    2. Their names must exactly match the class name.