Using java in FC1(with eclipse)-help needed

[Michael Kearey]

Mark Eggers wrote:
> On Tue, 2004-03-16 at 12:21, fedora-list-request at redhat.com wrote:
> 
> 
> 
>>Kaustubh Ghosh wrote:
> 
> 
>>I am quite novice towards java programming in linux.To start with I installed  
>>j2re1.4.2_03 and also j2sdk1.4.2_04 in FC1(Both from java.sin.com).Now 
>>peculiar problems arise.
>>When I type "java -version" it gives 1.3.1(
>>When I type "/usr/java/j2sdk1.4.2_04/bin/java -version" it gives 1.4.2_04.
>>Anyway  I  can compile any .java  file with javac.
>>But when I try to run it with java(any of the above) the gui would not 
>>come.(Hello World executes perfectly with System.out.println as also other 
>>non-gui programs).
> 
> 
> You have both Sun's Java and GNU's Java installed.  GNU's Java comes by
> default when you select all of the compilers during the install.

GNU's Java RPMS for Fedora do not include any 'java' executable. This 
is what gcc-java package has for executables:

/usr/bin/gcj
/usr/bin/gcjh
/usr/bin/jcf-dump
/usr/bin/jv-scan

And this is what libgcj has :

/usr/bin/gij
/usr/bin/grepjar
/usr/bin/jar
/usr/bin/jv-convert
/usr/bin/rmic
/usr/bin/rmiregistry

gij is the bytecode interpretor for GNU java - the equivalent of 
'java' executable BTW.


I really don't know how you can be so convinced that the java -version 
  that gives 1.3.1 is anything to do with GNU's java..

> 
> What I did was to find all the matching files in /usr that were supplied
> by Sun's J2SDK and moved them to a /usr/<directory>/orig.  I then added
> my $JAVA_HOME/bin and $JAVA_HOME/jre/javaws to my PATH variable.  javaws
> is where Java WebStart is located.
> 
> Like you, I have multiple Java versions installed.  I usually keep the
> current release and the previous release around in case something breaks
> in the current release that didn't break in the previous release.
> 
> To do this I make a symbolic link from where I installed Java to
> /usr/java.
> 
> For example, if I have j2sdk1.4.2_02 and j2sdk1.4.2_04 installed in
> /usr, I will link /usr/j2sdk1.4.2_04 to /usr/java.
> 
> I then set JAVA_HOME to /usr/java.
> 
> This arrangement seems to work reasonably well.  Another approach would
> be to not make the link to /usr/java and just set the JAVA_HOME
> environment variable appropriately.
> 
> However, in both cases you'll need to take the GNU commands out of your
> path and make sure that you have the Sun-supplied versions in your path.

I'd do 'which java' to see the java executable that is found in path. 
Also do 'rpm -qa |grep j2'  to see what, if any, RPMS are installed 
related to java 2...

Yes, and sort out the PATH to have the correct java executable needed..

Cheers,
Michael