Install Java 11 On Centos 7

admin14 April 2024Last Update :

Understanding Java 11 and CentOS 7 Compatibility

Java 11, released in September 2018, is a long-term support (LTS) version that brought several new features and updates to the Java platform. CentOS 7, on the other hand, is a stable, predictable, manageable, and reproducible platform derived from the sources of Red Hat Enterprise Linux (RHEL). Before diving into the installation process, it’s important to understand that Java 11 can run efficiently on CentOS 7, which provides a solid foundation for enterprise-grade systems.

Prerequisites for Installing Java 11 on CentOS 7

Before proceeding with the installation, ensure that you have:

  • A machine running CentOS 7.
  • Root or sudo privileges to execute administrative commands.
  • Access to a terminal or command line interface.
  • An active internet connection to download necessary files.

Choosing the Java 11 Distribution

There are multiple distributions of Java 11 available, including Oracle JDK, OpenJDK, and others like Amazon Corretto, AdoptOpenJDK, etc. For this guide, we will focus on installing OpenJDK 11 as it is open-source and freely available.

Step-by-Step Installation of OpenJDK 11 on CentOS 7

Updating System Packages

Firstly, update your system packages to the latest versions to avoid any conflicts during the installation process.

yum update -y

Installing OpenJDK 11

To install OpenJDK 11, use the following command:

yum install java-11-openjdk-devel -y

This command installs both the JDK (Java Development Kit) and JRE (Java Runtime Environment).

Verifying the Installation

After the installation completes, verify it by checking the Java version:

java -version

The output should display the installed version of Java, which should be Java 11.

Setting JAVA_HOME Environment Variable

For many Java applications, setting the JAVA_HOME environment variable is necessary. To find out where Java is installed, use the update-alternatives command:

update-alternatives --config java

Copy the path from the installation, and then set the JAVA_HOME variable in /etc/environment:

echo "JAVA_HOME=/usr/lib/jvm/java-11-openjdk" | sudo tee -a /etc/environment
source /etc/environment

Replace “/usr/lib/jvm/java-11-openjdk” with the actual path if different.

Configuring Alternatives

If there are multiple versions of Java installed, configure the default version using the alternatives system:

alternatives --config java

Select the number corresponding to Java 11 when prompted.

Post-Installation Tasks

Checking for Security Updates

Regularly check for security updates for Java 11 and keep the system updated:

yum update java-11-openjdk-devel

Setting Up Java 11 for Applications

Configure individual applications to use Java 11 by adjusting their respective configuration files to point to the correct JAVA_HOME.

Troubleshooting Common Java 11 Installation Issues on CentOS 7

Dealing with Conflicts Between Java Versions

If you encounter issues due to multiple Java versions, remove the ones not needed or use the alternatives system to switch between them.

Resolving Missing Dependencies

In case of missing dependencies, use yum to resolve them automatically or manually install the required packages.

Handling Network Issues During Installation

Ensure your network connection is stable. If a proxy is blocking downloads, configure yum to use the appropriate proxy settings.

Frequently Asked Questions

Can I install Oracle JDK 11 instead of OpenJDK 11?

Yes, you can install Oracle JDK 11 on CentOS 7, but it may require accepting a license agreement and downloading the package directly from Oracle’s website.

Is Java 11 free to use?

OpenJDK 11 is free to use under the GNU General Public License (GPL). Oracle JDK 11 is also free for development and testing, but commercial use may require a paid subscription.

How do I uninstall Java 11 if needed?

You can uninstall Java 11 using the following command:

yum remove java-11-openjdk-devel

What if I need to switch back to an older version of Java?

Use the alternatives system to switch between installed Java versions or uninstall Java 11 and reinstall the older version.

Are there any known compatibility issues with Java 11 on CentOS 7?

As of my knowledge cutoff date, there are no widespread compatibility issues reported. However, specific applications may have their own requirements or incompatibilities with Java 11.


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