Thursday, May 03, 2007

Downgrade default JRE on windows XP

When installing Blackberry signature keys yesterday, I need to downgrade my default JRE on windows XP from 1.6 to 1.5. (Java is so good at maintaining backward compatibility, I seriously want to figure out what made the installation process not working in Java1.6. If you have a clue, please comment. Thanks.)

The complexity of this process caught me off guard. As a linux user, I instinctively went to My Computer --> Properties --> Advanced --> Environment Variables, and set the pathes. It doesn't work this way though. (Gentoo users, enjoy your java-config util and laught at me)

After some digging, here are the steps worked for me.
  1. Copy java.exe, java2.exe, javaws.exe from C:\Program Files\Java\jdk1.5.0_??\bin to C:\WINDOWS\system32\ to overwrite existing 1.6 version files.
  2. Open registry editor, goto Start --> Run, type in "regedit" and enter.
  3. Do a search for "JavaSoft", you should find something under HKEY_LOCAL_MACHINE -->SOFTWARE --> JavaSoft --> Java Runtime Environment, modify "CurrentVersion" key to "1.5" or the version you want.
  4. Update the correspondent environment variables.
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3 comments:

  1. BenMarch 18, 2009 4:15 PM

    Thanks a lot, this saved me from having to uninstall/reinstall to downgrade then uninstall and reinstall back to 1.6.

    The article is as true today as when it was written :)

    ReplyDelete
  2. JekinJanuary 05, 2011 11:14 AM

    This comment has been removed by the author.

    ReplyDelete
  3. JekinJanuary 05, 2011 11:45 AM

    Just wondering, why you couldn't remove Java 6 from Control Panel->Add or Remove Programs? I just installed Java 1.5.0_22 then removed Java 6. Then go to this site:
    http://www.java.com/en/download/installed.jsp
    I see my Java version is 1.5.0_22

    ReplyDelete