How to completely remove Java? (Error: could not open `C:\Program Files\Java\jre6\lib\i386\jvm.cfg')

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+3 Q:

How to completely remove Java? (Error: could not open `C:\Program Files\Java\jre6\lib\i386\jvm.cfg')

I have passed the last couple of hours trying to downgrade Java to 1.6.0_13 in my attempt to get Google Web Toolkit's hosted mode to work on Eclipse.

And it has proven to be a nightmare-ish task!

In retrospect:
- All references to Java in the Control Panel -> Uninstall a Program tool have been removed
- Those that didn't want to be removed, have been forced to by Microsoft's "Windows Installer Cleanup Utility" - http://support.microsoft.com/default.aspx?scid=kb;en-us;290301
- An annoying folder called "JRE" was still sitting around, so I deleted it

Now, if I open a command prompt and type java, I still get:

Error: could not open `C:\Program Files\Java\jre6\lib\i386\jvm.cfg'

Which means that it's still hidden somewhere...

What else do I have to do to remove it completely?

It's been a while since I've done java work on windows, but I believe you need to make sure the javahome/jre/bin directory is in the system path. You probably will want to set the JAVA_HOME variable as well.

Steve B. 2009-06-29 19:15:13

+1 A:

If you want to downgrade Java you just need to set the JVM that Eclipse uses for compilation:

Window > Preferences > Java > Installed JREs

and then add a new JDK/JRE that you want, in your case Java 5 then check the box next to the JVM/JRE.

Jon 2009-06-29 19:17:38

I did that first, but in order to make sure it's not getting picked up again somehow, I want to remove it completely and install only the version I want.

Farinha 2009-06-29 19:23:38

You can also specify project specific: Project > Preferences > Java Compiler. Check "Enable project specific settings" and then select the "Compiler compliance level" value.

Flynn81 2009-06-29 19:24:23

If you want to use something with Eclipse you need Java for running Eclipse if I'm not totally mistaken

Janusz 2009-06-29 19:18:14

Make sure you edit your PATH environment variable to remove any reference to %JAVA_HOME%\bin.

Beyond that, it looks like Java is completely removed from your machine.

Cuga 2009-06-29 19:21:07

But shouldn't the command prompt error be different in that case? The error I'm getting when I try to run java makes me think that there's still some reference to it somewhere.

Farinha 2009-06-29 19:26:10

+6 A:

I find it surprising that it's so hard to remove. Anyway, to answer your question, I'd look for and delete:

c:\windows\system32\java.exe
c:\windows\system32\javaw.exe

Once those are deleted, you should be fine.

That said, I seem to be able to run GWT in hosted mode with Java 1.6.0_14 just fine.

Jack Leow 2009-06-29 19:23:45

That seems to have removed that last trace. Thanks! I just wonder why the hell doesn't the uninstaller take care of those as well...Regarding GWT, is the debug working as well? And what operating system are you on? Windows 7 here, which I'm starting to suspect is the one to blame...

Farinha 2009-06-29 19:30:51

I'm surprised the uninstaller didn't just take care of that as well. I am on Windows XP. Also, I just did a quick test, and I am able to get GWT host mode to run in debug mode, and I tried inserting a breakpoint, and was able to get the code to pause there, and step through it. Let me know if there's anything else you'd like to verify.

Jack Leow 2009-06-29 19:43:07

Corresponding to these system32\java's are registry entries under "HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Runtime Environment"

Andrew Niefer 2009-06-30 01:13:55

VirtualBox (so long as you have sensible amount of RAM) is great for getting back to a nice crispy-clean set-up.

Tom Hawtin - tackline 2009-06-29 19:24:52

ansaurus

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How to completely remove Java? (Error: could not open `C:\Program Files\Java\jre6\lib\i386\jvm.cfg')

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