How to install Java Development Kit (JDK) on openSUSE and SLES

You need a Java Development Kit (JDK) to develop and compile Java applications. Installing a JDK will also install the Java Runtime Environment (JRE), which is required to run Java applications.

OpenJDK and Oracle provide JDK that you can install on OpenSUSE and SUSE Linux Enterprise Server (SLES). Oracle's JDK may have some additional features not available in OpenJDK's JDK. Still, it's not available in the default package manager's default repositories and requires a few manual steps. This guide, however, will only cover installing OpenJDK's JDK.

You can install OpenJDK's JDK on OpenSUSE and SLES using zypper at the terminal. You can also install multiple versions of JDKs if required and choose one as the default version.

1. Launch terminal.
2. Update zypper's package list.

   > sudo zypper refresh
   [sudo] password for root: 
   Retrieving repository 'Update repository of openSUSE Backports' metadata ...............................[done]
   Building repository 'Update repository of openSUSE Backports' cache ....................................[done]
   Retrieving repository 'Non-OSS Repository' metadata ....................................................[done]
   Building repository 'Non-OSS Repository' cache .........................................................[done]
   Retrieving repository 'Main Repository' metadata .......................................................[done]
   Building repository 'Main Repository' cache ............................................................[done]
   Retrieving repository 'Update repository with updates from SUSE Linux Enterprise 15' metadata ..........[done]
   Building repository 'Update repository with updates from SUSE Linux Enterprise 15' cache ...............[done]
   Retrieving repository 'Main Update Repository' metadata ................................................[done]
   Building repository 'Main Update Repository' cache .....................................................[done]
   Retrieving repository 'Update Repository (Non-Oss)' metadata ...........................................[done]
   Building repository 'Update Repository (Non-Oss)' cache ................................................[done]
   All repositories have been refreshed.

3. Search for available JDK versions.

   > sudo zypper search openjdk-devel
   Loading repository data...
   Reading installed packages...
   
   S | Name                     | Summary                            | Type
   --+--------------------------+------------------------------------+--------
     | java-1_8_0-openjdk-devel | OpenJDK 8 Development Environment  | package
     | java-9-openjdk-devel     | OpenJDK 9 Development Environment  | package
     | java-10-openjdk-devel    | OpenJDK 10 Development Environment | package
     | java-11-openjdk-devel    | OpenJDK 11 Development Environment | package
     | java-17-openjdk-devel    | OpenJDK 17 Development Environment | package

4. Install your preferred JDK version.

   > sudo zypper --non-interactive install java-17-openjdk-devel
   Loading repository data...
   Reading installed packages...
   Resolving package dependencies...
   
   The following 3 NEW packages are going to be installed:
     java-17-openjdk java-17-openjdk-devel java-17-openjdk-headless
   
   3 new packages to install.
   Overall download size: 41.9 MiB. Already cached: 0 B. After the operation, additional 188.2 MiB will be used.
   ##### snipped

5. Check if installed javac version is correct.

   > javac -version
   javac 17.0.5
6. Install other JDK version if required.

   > sudo zypper --non-interactive install java-1_8_0-openjdk-devel
   Loading repository data...
   Reading installed packages...
   Resolving package dependencies...
   
   The following 4 NEW packages are going to be installed:
     java-1_8_0-openjdk java-1_8_0-openjdk-devel java-1_8_0-openjdk-headless lksctp-tools
   
   4 new packages to install.
   Overall download size: 68.8 MiB. Already cached: 0 B. After the operation, additional 115.1 MiB will be used.

7. Set default javac version if multiple JDK's are installed.

   > sudo update-alternatives --config javac
   There are 2 choices for the alternative javac (providing /usr/bin/javac).
   
     Selection    Path                                         Priority   Status
   ------------------------------------------------------------
   * 0            /usr/lib64/jvm/java-17-openjdk/bin/javac      2705      auto mode
     1            /usr/lib64/jvm/java-1.8.0-openjdk/bin/javac   1805      manual mode
     2            /usr/lib64/jvm/java-17-openjdk/bin/javac      2705      manual mode
   
   Press <enter> to keep the current choice[*], or type selection number: 1
   update-alternatives: using /usr/lib64/jvm/java-1.8.0-openjdk/bin/javac to provide /usr/bin/javac (javac) in manual mode

8. Check default javac version to confirm change.

   > javac -version
   javac 1.8.0_352