First Java Program : Introduction

• "First Java Program"! How many times you have heard of this phrase. Before learning any language, it's just like a tradition to write first program that is commonly called as the "Hello World" program. 
• We will be covering the complete description including the whole syntax and the procedure to run the program.

Writing : First  Java Program

Let us write our first Java program to print “Hello World! This is my first Java program. Save as hello.java

First Java Program : Code


First Java Program : Output

Explanation : First Java Program

• public is an access modifier.
• class is a keyword which is used in every Java program to declare a class before writing Java program.
• “FirstProgram” is the class name.
• static is a keyword which means we can call a method without creating its object. Since the main function is a static method no object is created by JVM to call main.
• main() is a function from where execution of a program starts.
• String[] args are string parameters passed in main and are used as command line arguments. If no String parameters are passed then Java gives an error.
• out.println() to print some text in output. Here System is a class , out is the object of System class and println() is a method.

Executing : First Java Program

• Type the below commands in command prompt
  • javac hello.java
  • java FirstProgram
• The other method which is more simple and easy to use is writing the programs on IDE's like,
  • Eclipse
  • Netbeans
• But we recommend to write your program in a text editor like Notepad++ and compile the program using command prompt.

Note : IDE stands for "Integrated Development Environment". It is a platform over which programs can be written across various languages. IDE provides developers the luxury to write, compile, execute and test the programs without the use of any external command.