structure in java program | structure in java

Java Program Structure

A java program may contain many classes of which only one class define a main method. Classes contain data member and data methods that operate on the data members of the class. Methods may contain data type declarations and executable statements.

A Java program consists of different sections. Some of them are mandatory but some are optional. The optional section can be excluded from the program depending upon the requirements of the programmer.

java program structure

General Structure of Java Program 

        

      A java program may contain one or more section and they are:-

    

    1.    Documentation Section

    2.    Package Statement

    3.    Import Statement

    4.    Interface Statement

    5.    Class Definitions

    6.    Main Method Class

 

o  Documentation Section- The documentation section comprise asset of comment lines giving the name of program, the author and other detail which the programmer would like to refer to all later stage. Comments must explain why and what of classes and how of algorithms. This would greatly help in maintaining the  program..

In addition to the two style of comments discussed earlier. Java also used third type of style of comment /**……*/Known as documentation section. This form is used for generating  documentation automatically.

o  Package Statement- The first step allow in java file is Package statement. This statement is declare as package name and informs the compiler that the classes defined here belong to this package.

Example:

   Package student;

The package statement is optional. That is, our class do not to be part of package.

o   Import Statement-  The next thing after package statement(but before any class definition) may be a number of Import statements. This is similar to the #include statement in C.

Example:

import student.test;

This statement instructs the interpreted to load the test class contained in the package student. Using import statement we can have access to classes that are part of other name  packages.

o   Interface Statement- A interface is like a class but include a group of method declarations. This is also an optional  section and is used when we wish to implement the multiple inheritance feature in the program.

o   Class Definitions- A java program may contain multiple class definitions. classes are the primary and essential element of a java program. These classes are used to map the object of real-world problem. the number classes used depends on the complexity of the problem.

o   Main Method Class- Since every java stand along requires a main method as its starting point, this class is the essential part of java program. A simple java program may contain only this part. The main method of this class create object of various classes and establish communication between them.

/* Simple program in java to print hello.*/

java program structure

Output:

java program