Uninstall Java on Ubuntu

To uninstall Java on Ubuntu you can follow these steps:

1. Check the installed Java version: Open a terminal and run the following command to see the installed Java version on your system:

   java -version
   

   This will display installed Java version information.

2. Uninstall OpenJDK: If OpenJDK is installed on your system, you can uninstall it using the following command:

   • If you have the default OpenJDK installed:

     sudo apt remove default-jdk
     

   • If you have a specific version of OpenJDK installed, for example 11:

     sudo apt remove openjdk-11-jdk
     

3. Uninstall Oracle Java: If you have installed Oracle Java, you can uninstall it by following the steps below:

   • First, find the name of the installed Java package:

     sudo update-alternatives --list java
     

   • Use the following command to remove each Java package:

     sudo update-alternatives --remove "java" "<path_to_java_binary>"
     

     Replace <path_to_java_binary> with the actual Java binary path, for example /usr/lib/jvm/java-11-openjdk-amd64/bin/java

4. Remove Java-related environment variables: Edit /etc/environmentthe file and delete the line containing the Java path. Open the file using the following command:

   sudo nano /etc/environment
   

   Delete the line containing the Java path in the file and save the file.

5. Update environment variables: Run the following command to update environment variables:

   source /etc/environment
   

After completing the above steps, Java will be successfully uninstalled. You can run java -versionthe command again to ensure that Java has been completely uninstalled.