Method

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A Java method is a collection of statements that are grouped together to perform an operation. When you call the System.out.println method, for example, the system actually executes several statements in order to display a message on the console.

Now you will learn how to create your own methods with or without return values, invoke a method with or without parameters, overload methods using the same names, and apply method abstraction in the program design.

Here is the source code of the above defined method called max(). This method takes two parameters num1 and num2 and returns the maximum between the two:

/** Return the max between two numbers */
public static int max(int num1, int num2) {
   int result;
   if (num1 > num2)
       result = num1;
   else
       result = num2;
  return result; 
}


A method definition consists of a method header and a method body. Here are all the parts of a method:

  • Modifiers: The modifier, which is optional, tells the compiler how to call the method. This defines the access type of the method.
  • Return Type: A method may return a value. The returnValueType is the data type of the value the method returns. Some methods perform the desired operations without returning a value. In this case, the returnValueType is the keyword void.
  • Method Name: This is the actual name of the method. The method name and the parameter list together constitute the method signature.
  • Parameters: A parameter is like a placeholder. When a method is invoked, you pass a value to the parameter. This value is referred to as actual parameter or argument. The parameter list refers to the type, order, and number of the parameters of a method. Parameters are optional; that is, a method may contain no parameters.
  • Method Body: The method body contains a collection of statements that define what the method does.