Java: Class Methods Part 2

Overloading Methods

• Have multiple methods of the same name but have different parameters either in number or type.

Overriding Methods

• This is the way in which methods that are inherited from a classes ancestors in the inheirantence chain are replaced or over-ridden by new methods.
• Even if you have created a method that overrides a superclass's method, you can still call this superclasses method by using the following:

         super.method(); 

Constructor Methods

• optional method, a default exists that does nothing.
• Special Kind of method called when creating an instance of a class that may perform any variety of operations including initializing variables, creating other objects, etc.
• Always have the same name as the class.
• Can have multiple constructors (overloaded) that take different inputs and can perform different operations.
• Has NO return type.
• If you write a class with a constructor with parameters and you intend to possibly use it as a Pareny class you need to make sure you also write a constructor with NO paramters. This is needed because: If the child class is defined with no constructors, it will automatically call super() which is the Parent's constructor with no arguments.
• Inside of a constructor, if you need to call the parents constructor, you can do so by simply adding the following line inside of your constructor:

        super(arg1, ....); 

Finalizer Methods

• Called just before the object is garbage-collected and its memory reclaimed. Must be defined as follows:

   protected void finalize() throws Throwable { ...}

  NOTE: the throws Throwable refers to errors/exceptions that could occur....we will discuss this later when we talk about exceptions!!!
• The default finalize() does nothing.
• You can call a parent's finalize() using:

      super.finalize();

• You can call finalize() yourself...it will not call the garbage collector.