Managing multiple Java versions on Ubuntu is essential for developers working on diverse projects. Different applications often require different versions of the Java Development Kit (JDK) or Java Runtime Environment (JRE), making it crucial to switch between these versions efficiently. Ubuntu provides powerful tools to handle this, and one of the most effective methods is using the update-java-alternatives
command.
Switching Between Java Versions
In this article, the process of switching between Java versions using updata-java-alternatives
will be shown. This specialized tool simplifies the management of Java environments by updating all associated commands (such as java
, javac
, javaws
, etc.) in one go.
A crucial component of development is Java version control, especially when working on many projects with different Java Runtime Environment (JRE) or Java Development Kit (JDK) needs. In order to prevent compatibility problems and ensure efficient development workflows, proper management ensures that the right Java version is utilized for every project.
You must check that the Java version to be used is compatible with the application, program, or software running on the system. Using the appropriate Java version ensures that the product runs smoothly and without any compatibility issues.
Newer versions of Java usually come with updates and security fixes, which helps protect the system from vulnerabilities. Using an out-of-date Java version may expose the system to security vulnerabilities.
Performance enhancements and optimizations are introduced with every Java version. For maximum performance, use a Java version that is specific to the application.
It is important to know which versions are installed on the system before switching to other Java versions. To check the current Java version, the java-common
package has to be installed. This package contains common tools for the Java runtimes including the update-java-alternatives
method. This method allows you to list the installed Java versions and facilitates switching between them. Use the following command to install the java-common
package:
sudo apt-get install java-common
Upon completing the installation, verify all installed Java versions on the system using the command provided below:
sudo update-java-alternatives --list
The report above shows that Java versions 8 and 11 are installed on the system. Use the command below to determine which version is being used at the moment.
java -version
The displayed output indicates that the currently active version is Java version 11.
Technically speaking, as long as there is sufficient disk space and the package repositories support it, the administrator of Ubuntu is free to install as many Java versions as they choose.
Follow the instructions below for installing multiple Java versions.
Begin by updating the system using the following command:
sudo apt-get update -y && sudo apt-get upgrade -y
To add another version of Java, run the command below.
sudo apt-get install <java version package name>
In this example, installing Java version 17 can be done by running:
sudo apt-get install openjdk-17-jdk openjdk-17-jre
Upon completing the installation, use the following command to confirm the correct and successful installation of the Java version:
sudo update-java-alternatives --list
To switch between Java versions and set a default version on Ubuntu Linux, you can use the update-java-alternatives
command.
sudo update-java-alternatives --set <java_version>
In this case, the Java version 17 will be set as default:
sudo update-java-alternatives --set java-1.17.0-openjdk-amd64
To check if Java version 17 is the default version, run the command:
java -version
The output shows that the default version of Java is version 17.
Managing and Switching Java Versions in Ubuntu
In conclusion, managing multiple Java versions on Ubuntu Linux using update-java-alternatives
is a simple yet effective process. By following the steps outlined in this article, users can seamlessly switch between different Java environments, ensuring compatibility with various projects and taking advantage of the latest features and optimizations offered by different Java versions. Because Java version management is flexible, developers may design reliable and effective Java apps without sacrificing system performance or stability.