OpenJDK as Java Platform
Contents
Java Platform
As of May 2019, OpenJDK 8 is the official Java platform supported by gCube. Legacy components work on JDK from Oracle and are still maintained, but active development is not done under this platform.
About OpenJDK
OpenJDK (Open Java Development Kit) is a free and open-source implementation of the Java Platform, Standard Edition (Java SE). It is the result of an effort Sun Microsystems began in 2006. The implementation is licensed under the GNU General Public License (GNU GPL) version 2 with a linking exception. Were it not for the GPL linking exception, components that linked to the Java class library would be subject to the terms of the GPL license. OpenJDK is the official reference implementation of Java SE since version 7.
OpenJDK Installation
Installation on Mac OS X
Software requirements:
Installation steps:
1) Add the distribution repository:
>$ brew tap AdoptOpenJDK/OpenJDK ==> Tapping adoptopenjdk/OpenJDK Cloning into '/usr/local/Homebrew/Library/Taps/ adoptopenjdk/homebrew-OpenJDK'... remote: Enumerating objects: 24, done. remote: Counting objects: 100% (24/24), done. remote: Compressing objects: 100% (18/18), done. remote: Total 24 (delta 12), reused 12 (delta 5), pack-reused 0 Unpacking objects: 100% (24/24), done. Tapped 14 casks (66 files, 81.8KB).
2) Look for available releases:
>$ brew search /adoptopenjdk/ ==> Casks adoptopenjdk adoptopenjdk11-jre adoptopenjdk12 adoptopenjdk12-openj9-jre adoptopenjdk8-openj9 adoptopenjdk10 adoptopenjdk11-openj9 adoptopenjdk12-jre adoptopenjdk8 adoptopenjdk8-openj9-jre adoptopenjdk11 adoptopenjdk11-openj9-jre adoptopenjdk12-openj9 adoptopenjdk8-jre adoptopenjdk9
3) Install version 8:
>$ brew cask install adoptopenjdk8 ==> Satisfying dependencies ==> Downloading .... ==> Verifying SHA-256 checksum for Cask 'adoptopenjdk8'. ==> Installing Cask adoptopenjdk8 ==> Running installer for adoptopenjdk8; your password may be necessary. ==> Package installers may write to any location; options such as --appdir are ignored. Password: installer: Package name is AdoptOpenJDK installer: Installing at base path / installer: The install was successful. adoptopenjdk8 was successfully installed!
4) Verify that OpenJDK 8 is the default Java platform now:
>$ java -version OpenJDK version "1.8.0_212" OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_212-b03) OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.212-b03, mixed mode)
Installation on Ubuntu
Software requirements:
- Advanced Package Tool, or APT
- sudo privileges for the current user
Installation steps: 1) Install the package:
$ sudo apt install openjdk-8-jdk
2) Set OpenJDK as default java platform:
$ sudo update-java-alternatives -s java-1.8.0-openjdk-amd64
3) Verify that OpenJDK 8 is the default Java platform now:
$ sudo update-alternatives --get-selections idlj manual /usr/lib/jvm/java-8-openjdk-amd64/bin/idlj jar manual /usr/lib/jvm/java-8-openjdk-amd64/bin/jar jarsigner manual /usr/lib/jvm/java-8-openjdk-amd64/bin/jarsigner java manual /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java java2groovy auto /usr/share/groovy/bin/java2groovy javac manual /usr/lib/jvm/java-8-openjdk-amd64/bin/javac ...
Configuration for the IDE
Eclipse
1) Add OpenJDK as JDK:
Select the menu Windows > Preferences. In the new windows, select Java -> Installed JRE .