6. Basic Commands for command prompt and Basic java program

Command Line Interface

Commands for Using Command Prompt -

Here are some common commands used in the Command Prompt:

1. 'dir'

   • Lists the contents of the current directory.
   • Example: 'dir'

2. 'cls'

   • Clears the screen.
   • Example: 'cls'

3. 'cd'

   • Changes the directory from the current folder to a specified folder.
   • Example: 'cd foldername'

4. 'cd..'

   • Moves up one directory level from the current folder to the parent folder.
   • Example: 'cd..'

5. 'drive name:'

   • Changes the drive.
   • Example: ' C:'

6. 'mkdir' or 'md'

   • Creates a new folder in the current directory.
   • Example: 'mkdir foldername' or 'md foldername'

7. 'javac -version'

   • Checks the version of the Java compiler.
   • Example: 'javac -version'

8. 'java -version'

• Checks the version of the Java Virtual Machine (JVM).
• Example: 'java -version'

These commands will help you navigate and manage directories, check Java versions, and perform various tasks in the Command Prompt.

Basic Java Program

class hello
          {      // Class block starts from here.
                   public static void main(string[]args)
                         {          // Method block starts from here.
                                    System.out.println("Hello world !!") ;
                         }           // Method block ends here.
           }      // Class block ends here.

This is a basic java program to print Hello world!!  where we have class name as hello.

Explanation of program

1. Class Declaration

   • class hello { ... }
   • Defines a class named hello. In Java, every application begins with a class definition.

2. Main Method

   • public static void main(String[] args) { ... }
   • The main method is the entry point of any Java application. It is a static method, which means it belongs to the class rather than instances of the class.

3. Print Statement

   • System.out.println("Hello world!!");
   • This line prints the text "Hello world!!" to the console. The System.out.println method is used to print output in Java.