Method Overloading

• A class can have more than 1 method with the same name, provided that its parameters differ in either
  • number
  • type
  • order

  For example,

public void foo( int a, float b )

is distinct from the method

public void foo( float b, int a )

• When this occurs, we say the method is overloaded.
• See applet of Fig. 4.16.
• An common example of method overloading is object constructors.

  For example, consider some constructors for the Color class.

  • public Color Color(float red, float green, float blue) // parameters are in [0, 1].
  • public Color Color(int red, int green, int blue) // parameters are in [0, 1, ..., 255].
• A method's signature can be viewed as a list:

  ( method name, type of parameter 1, type of parameter 2, ..., type of parameter N )

• Overloaded methods do not have to have the same number of parameters.
• When a method is invoked, the Java compiler checks to see if it matches one of the class's method signatures.
• If so, it uses that method, otherwise it reports a compile error.
• When you misspell a method name (e.g., drawstring instead of drawString) you get this message.
• Methods are not distinguished by their return type:

  If they match elsewhere, then you get a compile error when you define the class.