Chapter 2. Installing OpenJDK 8 on Red Hat Enterprise Linux

OpenJDK is an environment for developing and running a wide range of platform-agnostic applications, from mobile applications to desktop and web applications and enterprise systems. Red Hat provides an open source implementation of the Java Platform SE (Standard Edition) called OpenJDK.

Applications are developed using the JDK (Java Development Kit). Applications are run on a JVM (Java Virtual Machine), which is included in the JRE (Java Runtime Environment) and the JDK. There is also a headless version of Java which has the smallest footprint and does not include the libraries needed for a user interface. The headless version is packaged in the headless subpackage.

Note

If you are unsure whether you need the JRE or the JDK, it is recommended that you install the JDK.

The following sections provide instructions for installing OpenJDK on Red Hat Enterprise Linux:

2.1. Installing a JRE on RHEL using yum

You can install OpenJDK Java Runtime Environment (JRE) using the system package manager, yum.

Prequisites

  • Log in as a user with root privileges.

Procedure

  1. Run the yum command, specifying the package you want to install:

    $ sudo yum install java-1.8.0-openjdk

  2. Check that the installation works:

    $ java -version
    openjdk version "1.8.0_242"
    OpenJDK Runtime Environment (build 1.8.0_242-b08)
    OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)

2.2. Installing a JRE on RHEL using an archive

You can install OpenJDK Java Runtime Environment (JRE) using an archive. This is useful if the Java administrator does not have root privileges.

Note

To ease the upgrades for later versions create a parent directory to contain your JREs and create a symbolic link to the latest JRE using a generic path.

Procedure

  1. Download the latest version of the JRE archive for Linux.
  2. Extract the contents of the archive to a directory of your choice:

    $ mkdir ~/jres
    $ cd ~/jres
    $ tar -xf java-1.8.0-openjdk-1.8.0.242.b08-1.static.jre.openjdkportable.x86_64.tar.xz
  3. Create a generic path by using symbolic links to your JRE for easier upgrades:

    $ ln -s ~/jres/java-1.8.0-openjdk-1.8.0.242.b08-1.static.jre.openjdkportable.x86_64 ~/jres/java-8

  4. Configure the JAVA_HOME environment variable:

    $ export JAVA_HOME=~/jres/java-8
  5. Verify that JAVA_HOME environment variable is set correctly:

    $ printenv | grep JAVA_HOME
    JAVA_HOME=~/jres/java-8
    Note

    When installed using this method, OpenJDK will only be available for the current user.

  6. Add the bin directory of the generic JRE path to the PATH environment variable:

    $ export PATH="$JAVA_HOME/bin:$PATH"
  7. Verify that java -version works without supplying the full path:

    $ java -version
    openjdk version "1.8.0_242"
    OpenJDK Runtime Environment (build 1.8.0_242-b08)
    OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)
Note

You can ensure that JAVA_HOME environment variable persists for the current user by exporting the environment variable in ~/.bashrc.

2.3. Installing OpenJDK 8 on RHEL using yum

You can install OpenJDK using the system package manager, yum.

Prerequisites

  • Log in as a user with root privileges.

Procedure

  1. Run the yum command, specifying the package you want to install:

    $ sudo yum install java-1.8.0-openjdk-devel

  2. Check that the installation works:

    $ javac -version
    javac 1.8.0_242

2.4. Installing OpenJDK on RHEL using an archive

You can install OpenJDK using an archive. This is useful if the Java administrator does not have root privileges.

Note

To ease upgrades, create a parent directory to contain your JREs and create a symbolic link to the latest JRE using a generic path.

Procedure

  1. Download the latest version of the OpenJDK archive for Linux.
  2. Extract the contents of the archvie to a directory of your choice:

    $ mkdir ~/jdks
    $ cd ~/jdks
    $ tar -xf java-1.8.0-openjdk-1.8.0.242.b08-1.static.jdk.openjdkportable.x86_64.tar.xz
  3. Create a generic path by using symbolic links to your JRE for easier upgrades:

    $ ln -s ~/jdks/java-1.8.0-openjdk-1.8.0.242.b08-1.static.jdk.openjdkportable.x86_64 ~/jdks/java-8

  4. Configure the JAVA_HOME environment variable:

    $ export JAVA_HOME=~/jdks/java-8
  5. Verify that JAVA_HOME environment variable is set correctly:

    $ printenv | grep JAVA_HOME
    JAVA_HOME=~/jdks/java-8
    Note

    When installed using this method, OpenJDK will only be available for the current user.

  6. Add the bin directory of the generic OpenJDK path to the PATH environment variable:

    $ export PATH="$JAVA_HOME/bin:$PATH"
  7. Verify that javac -version works without supplying the full path:

    $ javac -version
    javac "1.8.0_242"
Note

You can ensure that JAVA_HOME environment variable persists for the current user by exporting the environment variable in ~/.bashrc.

2.5. Installing multiple major versions of OpenJDK on RHEL using yum

You can install multiple versions of OpenJDK using the system package manager, yum.

Prerequisites

  • A Red Hat Subscription Manager (RHSM) account with an active subscription that provides access to a repository that provides the OpenJDK versions you want to install.
  • You must have root privileges on the system.

Procedure

  1. Run the following yum commands to install the package:

    For OpenJDK 8

    $ sudo yum install java-1.8.0-openjdk

    For OpenJDK 11

    $ sudo yum install java-11-openjdk

  2. After installing, check the available java versions:

    $ sudo yum list installed "java*"
    
    Installed Packages
    java-1.8.0-openjdk.x86_64          1:1.8.0.272.b10-3.el8_3         @rhel-8-for-x86_64-appstream-rpms
    java-11-openjdk.x86_64             1:11.0.9.11-2.el8_3              @rhel-8-for-x86_64-appstream-rpms
  3. Check the current java version:

    $ java -version
    openjdk version "1.8.0_242"
    OpenJDK Runtime Environment (build 1.8.0_242-b08)
    OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)

Additional resources

2.6. Installing multiple major versions of OpenJDK on RHEL using an archive

You can install multiple major versions of OpenJDK by using the same procedures found in Installing a JRE on RHEL using an archive or Installing OpenJDK on RHEL using an archive using multiple major versions.

Note

For instructions how to configure the default OpenJDK version for the system, see Selecting a system-wide archive java version.

2.7. Installing multiple minor versions of OpenJDK on RHEL using yum

You can install multiple minor versions of OpenJDK on RHEL. This is done by preventing the installed minor versions from being updated.

Procedure

  1. Add the installonlypkgs option in /etc/yum.conf to specify the OpenJDK packages that yum can install but not update.

    installonlypkgs=java-<version>--openjdk,java-<version>--openjdk-headless,java-<version>--openjdk-devel

    Updates will install new packages while leaving the old versions on the system:

    $ rpm -qa | grep java-1.8.0-openjdk
    java-1.8.0-openjdk-1.8.0.242.b08-0.el8_1.x86_64
    java-1.8.0-openjdk-headless-1.8.0.242.b08-0.el8_1.x86_64
  2. The different minor versions of OpenJDK can be found in the /usr/lib/jvm/<minor version> files.

    For example, the following shows part of /usr/lib/jvm/java-1.8.0-openjdk-1.8.0:

    $ /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.242.b08-0.el8_1.x86_64/bin/java -version
    openjdk version "1.8.0_242"
    OpenJDK Runtime Environment (build 1.8.0_242-b08)
    OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)
    
    $ /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.172-7.b11.el7.x86_64/bin/java -version
    openjdk version "1.8.0_172"
    OpenJDK Runtime Environment (build 1.8.0_172-b11)
    OpenJDK 64-Bit Server VM (build 25.172-b11, mixed mode)

2.8. Installing multiple minor versions of OpenJDK on RHEL using an archive

Installing multiple minor versions is the same as Installing a JRE on RHEL using an archive or Installing OpenJDK on RHEL using an archive using multiple minor versions.

Note

For instructions how to choose a default minor version for the system, see Selecting a system-wide archive java version.