Slide 9.8: Member methods

Member Methods

A method is a block of code which only runs when it is called. You can pass data, known as parameters, into a method. Methods are used to perform certain actions, and they are also known as functions. The purpose of methods is to reuse code: define the code once, and use it many times.

Creating a Method
A method must be declared within a class. It is defined with the name of the method, followed by parentheses ( ).

public class MyClass {
  static void myMethod( ) {
    // code to be executed
  }
}

Java provides some pre-defined methods, such as System.out.println, but you can also create your own methods to perform certain actions. For the above code:

public means the class, method, or member is available for use by all other classes.
myMethod is the name of the method.
static means that the method belongs to the MyClass class and not an object of the MyClass class.
void means that this method does not have a return value.

Calling a Method
To call a method in Java, write the method’s name followed by two parentheses ( ) and a semicolon (;).

The example uses myMethod to print a text (the action):

public class MyClass {
  public static void main( String[ ] args ) {
    myMethod( );     // Output: "I just got executed!"
  }
  static void myMethod( ) {
    System.out.println( "I just got executed!" );
  }
}