Skip to main content

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 :)
Labels:

Comments

Post a Comment

Popular posts from this blog

Use Client Certificate Authentication with Java and RestTemplate

As a follow up of the  http://gochev.blogspot.com/2019/04/convert-pfx-certificate-to-jks-p12-crt.html  we now have a keystore and a truststore (if anyone needs) and we will use this keystore to send client side authentication using Spring's RestTemplate . First copy your keystore.jks and truststore.jks in your classpath, no one wants absolute paths right ?:) Again a reminder  The difference between truststore and keystore if you are not aware is(quote from the   JSSE ref guide ) :   TrustManager: Determines whether the remote authentication credentials (and thus the connection) should be trusted. KeyManager: Determines which authentication credentials to send to the remote host. The magic happens in the creation of SSLContext. Keep in mind the Spring Boot have a nice RestTemplateBuilder but I will not gonna use it, because someone of you might have an older version or like me, might just use a plain old amazing Spring. If you just want to use the keystore: final Stri
Post a Comment
Read more

Convert PFX certificate to JKS, P12, CRT

I recently had to use a PFX certificate for client authentication (maybe another post will be coming) and for that reason I had to convert it to a Java keystore (JKS).  We will create BOTH a truststore and a keystore, because based on your needs you might need one or the other.  The difference between truststore and keystore if you are not aware is(quote from the JSSE ref guide : TrustManager: Determines whether the remote authentication credentials (and thus the connection) should be trusted. KeyManager: Determines which authentication credentials to send to the remote host. Ok that's enough what you will need is openssl and Java 7+ ;) ! First let's generate a key from the pfx file, this key is later used for p12 keystore. openssl pkcs12 -in example.pfx -nocerts -out  example .key   Enter Import Password: MAC verified OK Enter PEM pass phrase: Verifying - Enter PEM pass phrase: As shown here you will be asked for the password of the pfx file, l
Post a Comment
Read more