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    Predefined Methods

                     The methods that are already defined in the packages of Java and available to use in the form of class
                     library are called predefined methods. They are also known as built-in methods. To use these methods,
                     we  first have  to import the  package  in  which  the class exists  that contains  the  desired  methods.
                     Examples of predefined methods are CharAt() and next(). To use the predefined methods, we need to
                     create an object of the class under which the function is defined.

                     For example,
                     Scanner sc = new Scanner (System.in);  // Defining the object "sc"
                     String s = sc.next();                        // Using the function next()
                     User-defined Methods

                     A  method  written  by  the  programmer according  to his  requirements is known  as a user-defined
                     method. It helps a programmer to write customised code according to the needs of a program. An
                     example of a user-defined function  is fact(), which  is written by  the programmer  to calculate the
                     factorial of a number.

                     DEFINING A METHOD

                     A  programmer can  define  a function  anywhere  inside  a class after declaring  the  data  members.
                     Following is the general syntax to define a function:

                     <Access_Specifier> <Return_Type> <Method_Name> (parameters)
                     {
                         Block of statements;
                     }
                     Let us take an example:

                                              Access Specifier
                                                                       Method name
                                                      Return type
                                                                                            Parameters
                                                 public void sum (int i, int j)
                                                 {                                             Statement in the
                                    Method body        System.out.println(i + j);
                                                                                              body of the method
                                                 }
                     Here, sum is the name of the method. The keyword void specifies that the method does not return any
                     value. The public keyword specifies that the method can be accessed from anywhere inside the class
                     and outside the class. In the body of the method, the sum of the values in i and j is printed.

                     Different Components of a Method

                     The various components of a method are:
                        Header of Method

                        Method Signature
                        Access Specifier

                        Return Type and Return Statement

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