How to check java version in linux

Question

What are the steps to determine the version of Java installed on a Linux system, and how can one ensure that the detected version is correctly configured for use?

Answer 1

Checking your Java version on a Linux machine can be done through the terminal using the following steps:

1. Open Terminal: You can open the terminal by searching for it in your system's applications menu, or by using the keyboard shortcut `Ctrl` + `Alt` + `T`.

2. Check Java Version: Once the terminal is open, type the following command and press Enter:  

 ```bash
     java -version

     ```

This command will display the version of Java that is currently in use on your machine.

3. Check All Installed Java Versions (Optional):
   If you have multiple versions of Java installed, you can use the following command to list all installed Java versions:

    ```bash
     update-java-alternatives --list
     ```

This will display a list of all installed Java versions along with their installation paths.

4. Check the Default Java Compiler (Optional):
   If you want to check the version of the default Java compiler (javac), use the following command:

     ```bash
     javac -version
     ```

This will display the version of the default Java compiler.

These commands should provide you with the information you need regarding the Java version(s) installed on your Linux machine.