How to install Java on CentOS 8

How to install Java on CentOS 8

Java is a free, open source and one of the most popular programming languages ​​specifically designed for the distributed environment of the Internet. There are two different implementations of Java, Oracle Java and OpenJDK. Oracle Java has some other commercial features, and OpenJDK is an open source implementation of the Java platform.

In this tutorial, we will show you how to install OpenJDK 8, OpenJDK 11 and Oracle 8 on CentOS 8.

Claim

  • Server 8 running CentOS.
  • A root password is set on your system.

Install OpenJDK 11

First, search the CentOS 8 repository for available OpenJDK versions by running the following command:

dnf search jdk

You should see the following output:

Last metadata expiration check: 1:23:41 ago on Wednesday 18 December 2019 02:23:23 AM EST.

========================================================= Summary & Name Matched: jdk =========================================================
java-11-openjdk-demo.x86_64 : OpenJDK Demos 11
java-1.8.0-openjdk-demo.x86_64 : OpenJDK Demos 8
java-11-openjdk-jmods.x86_64 : JMods for OpenJDK 11
java-11-openjdk-src.x86_64 : OpenJDK Source Bundle 11
java-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundle 8
java-11-openjdk.x86_64 : OpenJDK Runtime Environment 11
copy-jdk-configs.noarch : JDKs configuration files copier
java-1.8.0-openjdk.x86_64 : OpenJDK Runtime Environment 8
java-11-openjdk-javadoc.x86_64 : OpenJDK 11 API documentation
java-1.8.0-openjdk-javadoc.noarch : OpenJDK 8 API documentation
java-11-openjdk-devel.x86_64 : OpenJDK Development Environment 11
java-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environment 8
java-11-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 11
java-1.8.0-openjdk-accessibility.x86_64 : OpenJDK 8 accessibility connector
java-1.8.0-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 8
java-11-openjdk-javadoc-zip.x86_64 : OpenJDK 11 API documentation compressed in a single archive
java-1.8.0-openjdk-javadoc-zip.noarch : OpenJDK 8 API documentation compressed in a single archive
============================================================ Summary Matched: jdk =============================================================
icedtea-web.noarch : Additional Java components for OpenJDK - Java browser plug-in and Web Start implementation

Now install OpenJDK 11 using the following command:

dnf install java-11-openjdk-devel.x86_64

After the installation is complete, you can verify the installed Java version by running the following command:

java -version

You should see the following output:

openjdk version "11.0.5" 2019-10-15 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.5+10-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10-LTS, mixed mode, sharing)

Install OpenJDK 8

Some Java-based applications are only supported on OpenJDK 8. In this case, you will need to install OpenJDK 8 on the server. You can easily install OpenJDK 8 using the following command:

dnf install java-1.8.0-openjdk-devel

After installing Java, you can use the following command to check the installed version of Java:

java -version

You should see the following output:

openjdk version "1.8.0_232"
OpenJDK Runtime Environment (build 1.8.0_232-b09)
OpenJDK 64-Bit Server VM (build 25.232-b09, mixed mode)

Switch between Java versions

You can also install multiple versions of Java in a single system and switch between them as needed.

You can run the following command to switch the Java version from OpenJDK 8 to OpenJDK 11 as follows:

alternatives --config java

You will be asked to provide the required version of Java as follows:

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
   1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.5.10-0.el8_0.x86_64/bin/java)
*+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el8_0.x86_64/jre/bin/java)

Enter to keep the current selection[+], or type selection number: 1

Type 1 and press Enter to switch the Java version.

After making changes, check the currently active Java version again using the following command:

java -version

Install Oracle Java 8

First, you need to log in to the Oracle Java website and go to the Oracle Java 8 JDK download page. Next, accept the license agreement and download the jdk-8u231-linux-x64.rpm package.

After the download is complete, run the following command to install Oracle OpenJDK 8:

dnf localinstall jdk-8u231-linux-x64.rpm

After installing Oracle OpenJDK 8, you can verify the Java version using the following command:

java -version

You should see the following output:

java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)

in conclusion

That’s it for now. We learned how to install different versions of Java in CentOS 8. Now you can easily install the required Java versions and switch between them as needed.

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