Simple Java Program

To create a simple Java program, you need to create a class that contains the main method.

class Simple{  

    public static void main(String args[]){  

     System.out.println("Hello Java");  

    }  

}  

Save the above file as Simple.java.

To compile:    javac Simple.java

To execute:     java Simple

The meaning of class, public, static, void, main, String[], System.out.println() is:

• class keyword is used to declare a class in Java.
• public keyword is an access modifier that represents visibility. It means it is visible to all.
• static is a keyword. If we declare any method as static, it is known as the static method. The core advantage of the static method is that there is no need to create an object to invoke the static method. The main() method is executed by the JVM, so it doesn't require creating an object to invoke the main() method. So, it saves memory.
• void is the return type of the method. It means it doesn't return any value.
• main represents the starting point of the program. 
• String[] args or String args[] is used for command line argument
• System.out.println() is used to print statement. Here, System is a class, out is an object of the PrintStream class, println() is a method of the PrintStream class.