How can I change Mac OS s default Java VM returned from usr libexec java home

Question

Wasn t sure if this should go on SU    migration is certainly an option  but more programmers read questions here  so here goes    I am running Mac OS X 10 8 4  and I have Apple s JDK 1 6 0 51 installed as well as Oracle s JDK 1 7 0 25  I recently installed Oracle s 1 8 preview JDK for some pre-release software that requires it  Now  when I run  usr libexec java home  I get this      usr libexec java home -V Matching Java Virtual Machines  4       1 8 0  x86 64    Java SE 8   Library Java JavaVirtualMachines jdk1 8 0 jdk Contents Home     1 7 0 25  x86 64     Java SE 7   Library Java JavaVirtualMachines jdk1 7 0 25 jdk Contents Home     1 6 0 51-b11-457  x86 64     Java SE 6   System Library Java JavaVirtualMachines 1 6 0 jdk Contents Home     1 6 0 51-b11-457  i386   Java SE 6   System Library Java JavaVirtualMachines 1 6 0 jdk Contents Home   Great   However  running     java -version   Returns   java version  1 8 0-ea    That means that the default version of Java is currently the pre-release version  which breaks some  normal  packages  in my case  VisualVM    I can t set JAVA HOME because launching applications ignores environment variables  even when launching from the command line  e g    open  Applications VisualVM app    So  is there a file I can edit where I can set my JVM ordering preferences globally    Please don t tell me to launch the Java Preferences Panel because that simply does not work  it does not contain anything useful and only lists one of the 4 JVMs that I have installed    Update   Oracle JVMs live in  Library Java JavaVirtualMachines  Re-naming the JDK 1 8 directory to jdk1 8 0 jvm xyz does not change anything  java home still finds it in the right place  and running  usr bin java still executes the 1 8 JVM  This is not an issue with synlinks  etc   Answers to Similar Questions  While this answer offers what amounts to a hack that will remove versions of Java from being picked up by java home  it still does not answer this question of how java home chooses its default and whether or not users can non-destructively set it

User · Answer

I actually looked at this a little in the disassembler, since source isn't available.

/usr/bin/java and /usr/libexec/java_home both make use of JavaLaunching.framework. The JAVA_HOME environment variable is indeed checked first by /usr/bin/java and friends (but not /usr/libexec/java_home.) The framework uses the JAVA_VERSION and JAVA_ARCH envirionment variables to filter the available JVMs. So, by default:

$ /usr/libexec/java_home -V
Matching Java Virtual Machines (2):
    11.0.5, x86_64: "Amazon Corretto 11"    /Library/Java/JavaVirtualMachines/amazon-corretto-11.jdk/Contents/Home
    1.8.0_232, x86_64:  "Amazon Corretto 8" /Library/Java/JavaVirtualMachines/amazon-corretto-8.jdk/Contents/Home

/Library/Java/JavaVirtualMachines/amazon-corretto-11.jdk/Contents/Home

But setting, say, JAVA_VERSION can override the default:

$ JAVA_VERSION=1.8 /usr/libexec/java_home
/Library/Java/JavaVirtualMachines/amazon-corretto-8.jdk/Contents/Home

You can also set JAVA_LAUNCHER_VERBOSE=1 to see some additional debug logging as far as search paths, found JVMs, etc., with both /usr/bin/java and /usr/libexec/java_home.

In the past, JavaLaunching.framework actually used the preferences system (under the com.apple.java.JavaPreferences domain) to set the preferred JVM order, allowing the default JVM to be set with PlistBuddy - but as best as I can tell, that code has been removed in recent versions of macOS. Environment variables seem to be the only way (aside from editing the Info.plist in the JDK bundles themselves.)

Setting default environment variables can of course be done through your .profile or via launchd, if you need them be set at a session level.

User · Answer

It s pretty simple  if you don t mind rolling up your sleeves     Library Java Home is the default for JAVA HOME  and it s just a link that points to one of     System Library Java JavaVirtualMachines 1     jdk Contents Home  Library Java JavaVirtualMachines jdk1        jdk Contents Home   So I wanted to change my default JVM JDK version without changing the contents of JAVA HOME     Library Java Home is the standard location for the current JVM JDK and that s what I wanted to preserve    it seems to me to be the easiest way to change things with the least side effects   It s actually really simple  In order to change which version of java you see with java -version  all you have to do is some version of this   cd  Library Java sudo rm Home sudo ln -s  Library Java JavaVirtualMachines jdk1 8 0 60 jdk Contents Home   Home   I haven t taken the time but a very simple shell script that makes use of  usr libexec java home and ln to repoint the above symlink should be stupid easy to create     Once you ve changed where  Library Java Home is pointed    you get the correct result   cerebro   magneto  java -version java version  1 8 0 60  Java TM  SE Runtime Environment  build 1 8 0 60-b27  Java HotSpot TM  64-Bit Server VM  build 25 60-b23  mixed mode

User · Answer

Edit  this information is for visualvm specifically  not for any other java app  As mentioned by others  you need to modify the visualvm conf   For the latest version of JvisualVM 1 3 6 on Mac  the install directories have changed   It is currently in  Applications VisualVM app Contents Resources visualvm etc visualvm conf    However this may depend on where you have installed VisualVM  The easiest way to find where your VisualVM is to start it  and then look at the process using   ps -ef   grep VisualVM  You will see something like       -Dnetbeans dirs  Applications VisualVM app Contents Resources visualvm visualvm     You want to take the netbeans dir property and look up a directory and you will find the etc folder   Uncomment this line in the visualvm conf and change the path to the jdk  visualvm jdkhome   path to jdk    Additionally  if you are having slowness with your visualvm and you have a lot of memory  I would suggest greatly increasing the amount of memory available and running it in server mode   visualvm default options  -J-XX MaxPermSize 96m -J-Xmx2048m -J-Xms2048m -J-server -J-XX  UseCompressedOops -J-XX  UseConcMarkSweepGC -J-XX  UseParNewGC -J-XX NewRatio 2 -J-Dnetbeans accept license class com sun tools visualvm modules startup AcceptLicense -J-Dsun jvmstat perdata syncWaitMs 10000 -J-Dsun java2d noddraw true -J-Dsun java2d d3d false

User · Answer

I wanted to change default java version form 1 6  to 1 7   I tried the following steps and it worked for me    Removed link  java  from under  usr bin Created it again  pointing to the new location    ln -s  Library Java JavaVirtualMachines jdk1 7 0 51 jdk Contents Home bin java java   verified with  java -version    java version  1 7 0 51  Java TM  SE Runtime Environment  build 1 7 0 51-b13  Java HotSpot TM  64-Bit Server VM  build 24 51-b03  mixed mode

User · Answer

I tested  jenv  and other things like setting  JAVA HOME  without success  Now i and endet up with following solution  function setJava       export JAVA HOME     usr libexec java home -v  1       launchctl setenv JAVA HOME  JAVA HOME     sudo ln -nsf    dirname   JAVA HOME   MacOS   Library Java MacOS      java -version      added to    bashrc or    bash profile or    zshrc   And calling like that   setJava 1 8   java home will handle the wrong input  so you can t do something wrong  Maven and other stuff will pick up the right version now

User · Answer

I ve been there too and searched everywhere how  usr libexec java home works but I couldn t find any information on how it determines the available Java Virtual Machines it lists   I ve experimented a bit and I think it simply executes a ls  Library Java JavaVirtualMachines and then inspects the    lt version gt  Contents Info plist of all runtimes it finds there   It then sorts them descending by the key JVMVersion contained in the Info plist and by default it uses the first entry as its default JVM   I think the only thing we might do is to change the plist  sudo vi  Library Java JavaVirtualMachines jdk1 8 0 jdk Contents Info plist and then modify the JVMVersion from 1 8 0 to something else that makes it sort it to the bottom instead of the top  like  1 8 0   Something like    lt  xml version  1 0  encoding  UTF-8   gt   lt  DOCTYPE plist PUBLIC  -  Apple  DTD PLIST 1 0  EN   http   www apple com DTDs PropertyList-1 0 dtd  gt   lt plist version  1 0  gt   lt dict gt               lt dict gt                               lt key gt JVMVersion lt  key gt               lt string gt  1 8 0 lt  string gt     lt  -- changed from  1 8 0  to   1 8 0  -- gt     and then it magically disappears from the top of the list    usr libexec java home -verbose Matching Java Virtual Machines  3       1 7 0 45  x86 64     Java SE 7   Library Java JavaVirtualMachines jdk1 7 0 45 jdk Contents Home     1 7 0 09  x86 64     Java SE 7   Library Java JavaVirtualMachines jdk1 7 0 09 jdk Contents Home      1 8 0  x86 64   Java SE 8   Library Java JavaVirtualMachines jdk1 8 0 jdk Contents Home   Now you will need to logout login and then   java -version java version  1 7 0 45     -   Of course I have no idea if something else breaks now or if the 1 8 0-ea version of java still works correctly   You probably should not do any of this but instead simply deinstall 1 8 0   However so far this has worked for me

User · Answer

I had a similar situation  and the following process worked for me    In the terminal  type   vi    profile  Then add this line in the file  and save  export JAVA HOME  Library Java JavaVirtualMachines jdk lt version gt  jdk Contents Home   where version is the one on your computer  such as 1 7 0 25 Exit the editor  then type the following command make it become effective  source    profile     Then type java -version to check the result       java -version    What is  profile   From http   computers tutsplus com tutorials speed-up-your-terminal-workflow-with-command-aliases-and-profile--mac-30515      profile file is a hidden file  It is an optional file which tells the system which commands to run when the user whose profile file it is logs in  For example  if my username is bruno and there is a  profile file in  Users bruno   all of its contents will be executed during the log-in procedure

User · Answer

It s actually pretty easy  Let s say we have this in our JavaVirtualMachines folder    jdk1 7 0 51 jdk  jdk1 8 0 jdk   Imagine that 1 8 is our default  then we just add a new folder  for example  old   and move the default jdk folder to that new folder  Do java -version again et voila  1 7

User · Answer

I think JAVA HOME is the best you can do   The command-line tools like java and javac will respect that environment variable  you can use  usr libexec java home -v  1 7   to give you a suitable value to put into JAVA HOME in order to make command line tools use Java 7   export JAVA HOME    usr libexec java home -v  1 7       But standard double-clickable application bundles don t use JDKs installed under  Library Java at all   Old-style  app bundles using Apple s JavaApplicationStub will use Apple Java 6 from  System Library Frameworks  and new-style ones built with AppBundler without a bundled JRE will use the  public  JRE in  Library Internet Plug-Ins JavaAppletPlugin plugin Contents Home - that s hard-coded in the stub code and can t be changed  and you can t have two different public JREs installed at the same time     Edit  I ve had a look at VisualVM specifically  assuming you re using the  application bundle  version from the download page  and this particular app is not an AppBundler application  instead its main executable is a shell script that calls a number of other shell scripts and reads various configuration files   It defaults to picking the newest JDK from  Library Java as long as that is 7u10 or later  or uses Java 6 if your Java 7 installation is update 9 or earlier   But unravelling the logic in the shell scripts it looks to me like you can specify a particular JDK using a configuration file   Create a text file   Library Application Support VisualVM 1 3 6 etc visualvm conf  replace 1 3 6 with whatever version of VisualVM you re using  containing the line  visualvm jdkhome    usr libexec java home -v  1 7       and this will force it to choose Java 7 instead of 8

User · Answer

Oracle s uninstallation instructions for Java 7 worked for me   Excerpt      Uninstalling the JDK   To uninstall the JDK  you must have Administrator privileges and execute the remove command either as root or by using the sudo 8  tool       Navigate to  Library Java JavaVirtualMachines and remove the directory whose name matches the following format         Library Java JavaVirtualMachines jdk lt major gt   lt minor gt   lt macro  update  gt  jdk      For example  to uninstall 7u6         rm -rf jdk1 7 0 06 jdk

User · Answer

A bit late but as this is an ongoing issue with Mac OSX      The simplest solution I found was to simply remove the OpenJDK stuff that Apple installs  Every time an update of Mac OSX arrives it gets installed and you ll need to remove it again   This works really well if you develop apps for Google App Engine on your mac using Java  The OpenJDK does not work well and the Java version that comes with the Mac OSX Yosemite upgrade will make the Eclipse Plug-in for App Engine crash on every deployment with the helpful error   Read timed out

User · Answer

MacOS uses  usr libexec java home to find the current Java Version   One way to bypass is to change the plist file as explained by  void256 above   Other ways is to take the backup of the java home and replace it with your own script java home having the code         echo  JAVA HOME  Now export the JAVA HOME to the desired version of the SDK by adding the following commands to the    bash profile          export JAVA HOME   System Library Java JavaVirtualMachines 1 6 0 jdk Contents Home          launchctl setenv JAVA HOME  JAVA HOME          Make the environment variable global  Run the command source    bash profile to the run the above commands    Anytime one needs to change the JAVA HOME he can reset the JAVA HOME value in the    bash profile file

[java] How can I change Mac OS's default Java VM returned from /usr/libexec/java_home

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