JRE Installed?

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Is there some way for me to sense whether the Java Runtime Engine is
installed, and perhaps what version it is?

Mike Hanson
www.boxsoft.net

[NewsArchive]

Hi Mike,

> Is there some way for me to sense whether the Java Runtime Engine is
> installed, and perhaps what version it is?

As I understand it, there can be any number of installed JREs and JDKs on a
Windows machine, but only one will have the
HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment registry item
set.

So I think the above registry can be used to detected an installed JRE
(including the version). The "CurrentVersion" value should store the
version number string.

Friedrich

[NewsArchive]

Thanks, Friedrich. I also found the following in the IPServer's
run.bat:

if "%JAVA_HOME%"=="" goto no_javahome
if not exist "%JAVA_HOME%\bin\java.exe" goto no_javahome

I have to decide whether to provide a web link for installing the JRE,
or to just warn them to do it.

BTW, I'm about to send you a big message on my thoughts regarding the
IPServer installation.

Mike Hanson
www.boxsoft.net

[NewsArchive]

Hmmm. My machine doesn't have that registry key, and I don't have a
%JAVA_HOME% environment variable, but I definitely have the JRE
installed.

I just dug around, and I've got some stuff in
HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Runtime Environment, but
it's just a folder with a single 1.6.0_23 subfolder. The subfolder
has a single "BalloonShown" boolean entry. Therefore, I suspect this
is a "settings" entry, rather than the official marker that the JRE is
installed.

I've got some other stuff beneath "Wow6432Node", but that doesn't
sound generic enough for my purposes.

Mike Hanson
www.boxsoft.net

[NewsArchive]

Mike,

I found the following:

http://www.oracle.com/technetwork/java/javase/runtime-windows-137915.html

As I understand it, the only way to detect the runtime is via the

HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Runtime Environment

key.

You can then use "Get Registry SubKey" to detect subkeys and (if available)
read the version and installation path.

But I think that one of the Jave patches introduced a problem and so
"JavaHome" is not always set:

http://forum.bigfix.com/viewtopic.php?id=6872
http://forum.bigfix.com/viewtopic.php?pid=29104#29104

Friedrich

[NewsArchive]

For whatever reason, I don't have that key on my system, but I
definitely have the JRE (1.6, I believe). Strange.

Mike Hanson
www.boxsoft.net

[NewsArchive]

Better call Dr JRE

Jeff Slarve
www.jssoftware.com
www.twitter.com/jslarve

[NewsArchive]

Yo, yo!

Mike Hanson
www.boxsoft.net