How do I set the default Java installation runtime Windows

Question

I m in the situation where I ve installed the JDK  but I can t run applets in browsers  I may not have installed the JRE    However  when I install the JRE  it clobbers my JDK as the default runtime   This breaks pretty much everything  Eclipse  Ant  - as they require a server JVM   There s no JAVA HOME environment variable these days - it just seems to use some registry magic  setting the system path is of no use either    Previously  I ve just uninstalled the JRE after I ve used it to restore the JDK   This time I want to fix it properly   This also manifests itself with the jre autoupdater - once upon a time  I had a working setup with the JDK and JRE  but it updated and bust everything

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I simply install all the versions of JDK I need and the latest installed becomes default  so I just reinstall the one I want to be default if necessary

User · Answer

After many attempts  I found the junction approach more convenient  This is very similar on how this problem is solved in linux   Basically it consists of having a link between c  tools java default and the actual version of java you want to use as default in your system     How to set it    Download junction and make sure to put it in your PATH environment variable Set your environment this way      - PATH pointing to ONLY to this jre c  tools java default bin      - JAVA HOME pointing to  c  tools java default Store all your jre-s in one folder like  if you do that in your Program FIles folder you may encounter some    C  tools Java JRE 1 6 C  tools Java JRE 1 7 C  tools Java JRE 1 8  Open a command prompt and cd to C  tools Java   Execute junction default JRE 1 6   This will create a junction  which is more or less like a symbolic link in linux  between C  tools java default and C  tools java JRE 1 6  In this way you will always have your default java in c  tools java default    If you then need to change your default java to the 1 8 version you just need to execute  junction -d default junction default JRE 1 8    Then you can have batch files to do that without command prompt like  set jdk8 bat set jdk7 bat  As suggested from                EDIT  From windows vista  you can use mklink  J default JRE 1 8

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I have several JDK  1 4  1 5  1 6  installed in C  Java with their JREs  Then I let Sun update the public JRE in C  Program Files Java  Lately there is an improvement  installing in jre6  Previously  there was a different folder per new version  1 5 0 4  1 5 0 5  etc    which was taking lot of space

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Need to  remove C  Program Files  x86  Common Files Oracle Java javapath from environment and replace by JAVA HOME which is works fine for me

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Stacked by this issue and have resolved it in 2020  in Windows 10  I m using Java 8 RE and 14 1 JDK and it worked well until Eclipse upgrade to version 2020-09  After that I can t run Eclipse because it needed to use Java 11 or newer and it found only 8 version  It was because of order of environment variables of  quot Path quot    I suppose C  Program Files  x86  Common Files Oracle Java javapath is path to link to installed JRE exe files  in my case Java 8  and the issue was resolved by move down this link after  JAVA HOME   what leads to Java 14 1 bin folder   It seems that order of environment variables affects order of searched folders while executable file is requested  Thanks for your comment or better explanation

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an alterable way to run an  jar app is create an  bat cmd for it  for example  you have jre10 and jre8 installed on your pc and jre10 is your default jre  but your jar is specified to work with jre8 following cmd will work    C  Program Files Java jre1 8 0 181 bin java exe  -jar JabRef-4 3 1 jar

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I have patched the behaviour of my eclipse startup shortcut in the properties dialogue from  quot E  Program Files eclipse eclipse exe quot   to  quot E  Program Files eclipse eclipse exe quot  -vm  quot E  Program Files Java jdk1 6 0 30 bin quot   as described in the Eclipse documentation It is a patch only  as it depends on the shortcut to fix things    The alternative is to set the parameter permanently in the eclipse initialisation file

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This is a bit of a pain on Windows  Here s what I do   Install latest Sun JDK  e g  6u11  in path like c  install jdk sun 6u11  then let the installer install public JRE in the default place  c  program files blah   This will setup your default JRE for the majority of things   Install older JDKs as necessary  like 5u18 in c  install jdk sun 5u18  but don t install the public JREs   When in development  I have a little batch file that I use to setup a command prompt for each JDK version  Essentially just set JAVA HOME c  jdk sun JDK DESIRED and then set PATH  JAVA HOME  bin  PATH   This will put the desired JDK first in the path and any secondary tools like Ant or Maven can use the JAVA HOME variable   The path is important because most public JRE installs put a linked executable at c  WINDOWS System32 java exe  which usually overrides most other settings

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I just had that problem  Java 1 8 vs  Java 9 on Windows 7  and my findings are   short version  default seems to be  because of Path entry   c  ProgramData Oracle Java javapath java -version   select the version you want  test  use tab completing in cmd  not sure what those numbers represent   I had 2 options  see longer version for details  c  ProgramData Oracle Java javapath target  tab    remove junction link and link to your version  the one ending with 181743567 in my case for Java 8   rmdir javapath mklink  D javapath javapath target 181743567   longer version   Reinstall Java 1 8 after Java 9 didn t work  The sequence of installations was jdk1 8 0 74  jdk-9 0 4 and attempt to make Java 8 default with jdk1 8 0 162     After jdk1 8 0 162 installation I still have  java -version java version  9 0 4  Java TM  SE Runtime Environment  build 9 0 4 11  Java HotSpot TM  64-Bit Server VM  build 9 0 4 11  mixed mode    What I see in path is  Path     C  ProgramData Oracle Java javapath       So I checked what is that and I found it is a junction  link   c  ProgramData Oracle Java gt dir  Volume in drive C is OSDisk  Volume Serial Number is DA2F-C2CC   Directory of c  ProgramData Oracle Java  2018-02-07  17 06     lt DIR gt             2018-02-07  17 06     lt DIR gt              2018-02-08  17 08     lt DIR gt            oracle jre usage 2017-08-22  11 04     lt DIR gt           installcache 2018-02-08  17 08     lt DIR gt           installcache x64 2018-02-07  17 06     lt JUNCTION gt      javapath  C  ProgramData Oracle Java javapath target 185258831  2018-02-07  17 06     lt DIR gt           javapath target 181743567 2018-02-07  17 06     lt DIR gt           javapath target 185258831   Those hashes doesn t ring a bell  but when I checked  c  ProgramData Oracle Java javapath target 181743567 gt   java -version java version  1 8 0 162  Java TM  SE Runtime Environment  build 1 8 0 162-b12  Java HotSpot TM  64-Bit Server VM  build 25 162-b12  mixed mode   c  ProgramData Oracle Java javapath target 185258831 gt   java -version java version  9 0 4  Java TM  SE Runtime Environment  build 9 0 4 11  Java HotSpot TM  64-Bit Server VM  build 9 0 4 11  mixed mode    so to make Java 8 default again I had to delete the link as described here  rmdir javapath   and recreate with Java I wanted  mklink  D javapath javapath target 181743567   tested   c  ProgramData Oracle Java gt java -version java version  1 8 0 162  Java TM  SE Runtime Environment  build 1 8 0 162-b12  Java HotSpot TM  64-Bit Server VM  build 25 162-b12  mixed mode       update  Java 10      With Java 10 it is similar  only javapath is in c  Program Files  x86  Common Files Oracle Java  which is strange as I installed 64-bit IMHO    java -version java version  10 0 2  2018-07-17 Java TM  SE Runtime Environment 18 3  build 10 0 2 13  Java HotSpot TM  64-Bit Server VM 18 3  build 10 0 2 13  mixed mode

[java] How do I set the default Java installation/runtime (Windows)?

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