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Use Multiple JVM versions on Mac OS and Linux

Linux


Download multiple Java versions and put them into /opt/ If you already have some JDK from ubuntu repo or etc not a big deal, just fix the paths bellow

  • Register them as alternatives


sudo update-alternatives --install /usr/bin/java java /opt/java-8-oracle/bin/java 1081
sudo update-alternatives --install /usr/bin/java java /opt/sap-machine-jdk-11.0.3/bin/java 1080


  • Edit your ~/.bashrc file


alias java11='sudo update-alternatives --set java /opt/sapmachine-jdk-11.0.3/bin/java;export JAVA_HOME=/opt/sapmachine-jdk-11.0.3/'

 alias java8='sudo update-alternatives --set java /opt/java-8-oracle/bin/java;export JAVA_HOME=/usr/lib/java-8-oracle/'


  • SAVE and start a new bash terminal

execute

java8 to use java8
java11 to use java11

the latest version you have set stays as system wide, but the JAVA_HOME is not :( you can put java8 or java11 as a last line in the bashrc but since it is sudo it will always require password when start and is not great ;(

Mac


  • Install homebrew, since it rox !


  • Install Oracle Java 8 or OpenJDK 8.


I recommend adoptopenjdk

brew tap adoptopenjdk/openjdk
brew search adoptopenjdk
brew cask install adoptopenjdk8
brew cask install adoptopenjdk11


On mac since it RULZ you have a java_home executable (that changes and fixes both your path and your JAVA_HOME) , so the .bashrc changes are easy !


  • Edit your ~/.bashrc file



export JAVA_8_HOME=$(/usr/libexec/java_home -v1.8)

 export JAVA_11_HOME=$(/usr/libexec/java_home -v11)

 alias java8='export JAVA_HOME=$JAVA_8_HOME'
alias java11='export JAVA_HOME=$JAVA_11_HOME'

 java8

Note: the latest execution of java8 is to make it system wide by default


  • SAVE and start a new bash terminal


execute

java8 to use java8


java11 to use java11


Windows

Use a normal OS or suffer :)
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