To run your first Java program,
- you must have JDK installed on your PC
- You must set path JDK/bin
To write a simple HelloWorld program
- Create a file named HelloWorld.java
- Write the code as below
- Compile and Run
Code:
/** * This program prints "Hello World!" in the console. */ class HelloWorld { public static void main(String[] args) { System.out.println("Hello World"); } }
Output:
Hello World
Class definition:
class is a keyword and HelloWorld is the class name. Below is the class definition in HelloWorld.java.
class HelloWorld { --- --- --- }
Main method:
Every Java application must have a main method. Below is the main method in HelloWorld.java
public static void main(String[] args) { --- }
Print Statement:
System is a Class out is a Variable println() is a method. below is the print statement which will print the “Hello World” in the console.
System.out.println("Hello World");
Code comments:
Code comments will be ignored by the compiler. And these are very useful to other programmers. Below are the code comments in HelloWorld.java
/** * This program prints "Hello World!" in the console. */