Java Programmes

We can develop two types of Java Programmes

• Stand –alone applications
• Web applets

Stand –alone applications

An application is a normal program which is  executed as a normal programme (Can’t run on the web browsers)

Executing stand-alone Java program involves two steps

            Compiling  source code into byte code using java compiler

            Executing the byte code program using java interpreter

Web applets

An applet is a tiny applications that is executed  in the world wide web on the internet. To run  it should first be attached  to a web page using HTML. An applet located on a distant computer can be downloaded via internet and executed  on a local computer  using a java  capable browser.  We can develop  applet  for doing everything  form simple animated graphics  to complex  games and utilities.

Simple Java Programme

public class HelloWorld

            {

                        Public static void main(string args[])

                                    {

                                                 System.out.println (“Hello World”);

                                    }

}

• Name of the  class is Student. The keyword public tells that it can be accesses from other classes.
• Open brace bracket and close  brace bracket indicate the beginning  and end of the class  {       }
• Student class has only one method. It is called main(). Main() is like a main programe. It is  a class  method meaning that it works on the class  it self rather than  on the  objects. The keyword  static tells  this.
• The main () has one incoming parameter an array object called arg[] belong into string type. It accepts command  line arguments.
• The keyword  void says that the method does not  return any values
• System.out.println is  a command which displays  something on the screen