Defining Classes in Java

    The syntax for declaring classes is quite rigid.  In what appears
    below, anything contained inside angle brackets is information
    provided by you.  Everything else is to be taken literally, with
    the exception of spaces, tabs, and newlines which can be used
    in any fashion.  Any phrase starting with // is a comment and is not
    part of the class declaration.

  
class <classname>  
  {

    <modifiers> <data type> <variables>;    // this line can be repeated
                                            // any number of times.

    <modifiers> <return type> <methodname> ( <parameters>)
        {
           <method body>
        }
   }


EXAMPLE:

public class Book
{
   private int isbnNumber;      
    
   public void loadIsbnNumber(int num)      
      {
         isbnNumber = num; 
 
      }
    
   public int getIsbnNumber()   
      {
           return isbnNumber;
            
      }
}


USAGE:

   Book myBook;

   myBook = new Book();
   
   myBook.loadIsbnNumber(12345);
   System.out.println(myBook.getIsbnNumber());

CREATE COMPLETE JAVA PROGRAM

public class MySimpleProgram {

    public static void main(String args[])  // public static are modifiers
                                            // void is return type
                                            // main is the (required)
                                            // method name
                                            // args[] is a parameter
      {
         Book myBook;
         myBook = new Book();
         myBook.loadIsbnNumber(12345);
         System.out.println(myBook.getIsbnNumber()); 
      }                                       
}