It is said that the best way to learn swimming is to jump into the water right away. Similarly, the best way to learn a programming language is to start coding straight away. Let us start our study of Java programming in an informal way. Let us write a simple Java program and run it.

3.1 Introduction

In our first Java program, we will find the area of a circle with radius 5.

Problem: Write a program to find area of a circle with radius 5.

Solution: See Program 3.1.


PROGRAM 3.1 Area of a Circle


 class first


 public static void main( String args[] )


   int r ;

   r = 5 ;

   System.out.println(3.14 * r * r);



If you run the program, you will get the following output.



 78.5 ...

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