Sun & Blackdown Java on the same computer?

Nathan1993 · 03-29-2006, 01:04 PM

I am a noobie, and in my confusion I believe I have installed Sun & Blackdown java on the same computer! I am using Ubuntu Breezy Badger with all the latest updates. Does anyone know how I can check if I have them both, and if I do have them both, how to uninstall the Blackdown verison?

I have nothing against the Blackdown version, I would just rather have Sun's *real* Java than Blackdown's version. Also, Java is working fine in applets, programs, and when I type "java -version" I get...

java version "1.4.2-02"
Java(TM) 2 Runtime Environment, Standard Edition (build Blackdown-1.4.2-02)
Java HotSpot(TM) Client VM (build Blackdown-1.4.2-02, mixed mode)

Thanks in advance!

lel800 · 03-29-2006, 02:25 PM

It might not be necessary to uninstall the blackdown version ( though I agree it would be preferable ) but operationally, it may be enough to update the PATH environment variable. It looks like right now it includes the bin directory for black down. You will want to remove that directory from the PATH listing and replace it with the bin directory for the java install by Sun. Look inside the directory
/usr/java for a subdirectory j2sdk<version>. That I believe is where the 1.4.2 version would be installed if the rpm was used.

Nathan1993 · 03-29-2006, 03:28 PM

There is no /usr/java directory. Does that mean I do not have Sun's Java installed?

Grtz

Vgui · 03-29-2006, 07:11 PM

You can have any number of Java versions and types installed. I personally keep version 1.3, 1.4, and the latest 5.0 around.
Basically, it comes down to your JAVA_HOME environment variable, and where the java and javac binaries are pointing.
To get a feel for how your system is setup now, try (at the command line):

Code:

echo $JAVA_HOME
which java
which javac

Let's say that JAVA_HOME points to the Blackdown JVM (which is likely), you can simple edit .bashrc (in your home directory) and make JAVA_HOME point to where you want.
The other possibility is that java / javac is a link to the Blackdown JVM. You can tell this if the above "which" commands display something like:

Code:

javac -> /usr/share/blackdown/bin/javac

In this case, you can make a new link to the Java version you want, and maybe a different name for the Blackdown JVM:

Code:

ln -s /usr/share/java/jdk1.4.2/bin/javac /usr/local/bin/javac
ln -s /usr/share/blackdown/bin/javac /usr/local/bin/javac-blackdown

I hope you get the general idea here, basically you either reset your JAVA_HOME variable, or change which java binaries are called. Let me know if you need more help.