path setting in Linux for java3d

[tony_l...@yahoo.com]

Dear Friends,
I am new in Linux although I wrote Java codes under windows for some
times. Question here:

I tried to run java 3d in Linux, here is the steps:

1. download the following 4 files which are necessary for the
installation:
java3d-re-1.3-beta2-linux-i386.bin
java3d-sdk-1.3-beta2-linux-i386.bin
LICENSE-Java3D-1.3-beta2.txt
README-Java3D-1.3-beta2.txt

2.become root:
% su root
Password: enter root password
#

3. bash java3d-re-1.3-beta2-linux-i386.bin
yes
bash java3d-sdk-1.3-beta2-linux-i386.bin

4. exit the root.

5. demo/java3d/HelloUniverse$ java HelloUniverse
Exception in thread "main" java.lang.NoClassDefFoundError:
javax/media/j3d/Node

WHen I tried to run HelloUniverse, there is error:
NoClassDefFoundError: javax/media/j3d/Node.

I am sure that this is the problem of path setting. But how?
Thanks a lot for your hints.

btw. I guess that I should post this question into
comp.lang.java.java3d. But there are much less visitor there and I
always can not get answer. So I have to post this question here. Sorr.y
tony

[Gordon Beaton]

On 31 Aug 2005 11:49:20 -0700, tony_l...@yahoo.com wrote:
> WHen I tried to run HelloUniverse, there is error:
> NoClassDefFoundError: javax/media/j3d/Node.
>
> I am sure that this is the problem of path setting. But how?
> Thanks a lot for your hints.

You should be in the jre root (e.g. $JAVA_HOME/jre) when you do your
step 3, so the jarfiles end up in $JAVA_HOME/jre/lib/ext.

/gordon

--
[ do not email me copies of your followups ]
g o r d o n + n e w s @ b a l d e r 1 3 . s e

[tony_l...@yahoo.com]

sorry for my stupid quesiton here:
How do I know where JAVA_HOME is? which command? I know how it works in
WIndows, but not Linux...
THanks a lot.
Tony

[Gordon Beaton]

On 31 Aug 2005 12:11:28 -0700, tony_l...@yahoo.com wrote:
> How do I know where JAVA_HOME is? which command? I know how it works
> in WIndows, but not Linux...

$JAVA_HOME should refer to the top level directory of your JDK
installation. Where did you install the JDK?

"echo $JAVA_HOME" will tell you the value of JAVA_HOME, if there is
such a variable (there might not be one).

Or try typing "type -a javac" to find out where to start looking for
the JDK. Javac *should* be in the bin directory of your JDK, but it
*could* be somewhere else, for example if it's a symbolic link.

[tony_l...@yahoo.com]

Thank you very much! $JAVA_HOME is ~/java/j2sdk1.4.2_08, I tried the
following:

rakta:~/java/j2sdk1.4.2_08/demo/java3d/HelloUniverse$ javac
HelloUniverse.java
rakta:~/java/j2sdk1.4.2_08/demo/java3d/HelloUniverse$ java

HelloUniverse
Exception in thread "main" java.lang.NoClassDefFoundError:
javax/media/j3d/Node

This means, javac can work, but java can not. Shall I set some
classpath?
Thanks in advance!
tony.

[Gordon Beaton]

On 1 Sep 2005 01:58:06 -0700, tony_l...@yahoo.com wrote:
> This means, javac can work, but java can not. Shall I set some
> classpath?

Sorry I didn't notice that you downloaded both java3d-sdk and
java3d-re. These packages unpack into slightly different paths, and
consequently you need to be in a different place when you unpack them.

The jar files should end up in $JAVA_HOME/jre/lib/ext, as I mentioned
earlier, and the library (.so) files in $JAVA_HOME/jre/lib/i386. If
the files are there, then both javac and java should work.

To unpack java3d-sdk, you should be in JAVA_HOME (the root dir of your
JDK).

To unpack java3d-re, you should be in JAVA_HOME/jre. Note that if you
already unpacked the sdk, you don't need the jre.

[tony_l...@yahoo.com]

I did the following:
1. unpack java3d-re in JAVA_HOME/jre.
2. Then I tried:

rakta:~/java/j2sdk1.4.2_08/demo/java3d/HelloUniverse$ java
HelloUniverse
Exception in thread "main" java.lang.NoClassDefFoundError:
javax/media/j3d/Node

Still the same error. This means that java can not find the package
javax.
3. Then I set:
export CLASSPATH=./:$HOME/.lib:$JAVA_LOCAL/lib:$JAVA_HOME/jre/lib/ext
$JAVA_HOME/jre/lib/ext is where jar files stays. But it still can not
work.
Why?

[Chris Uppal]

tony_l...@yahoo.com wrote:

> rakta:~/java/j2sdk1.4.2_08/demo/java3d/HelloUniverse$ java
> HelloUniverse
> Exception in thread "main" java.lang.NoClassDefFoundError:
> javax/media/j3d/Node

I wonder if "java" is finding the wrong java installation. As far as I know,
setting the CLASSPATH isn't necessary for properly installed java "extensions"
(javax.* packages). You could try typing:

type java

if that doesn't reply something like:

java is <somewhere>/bin/java

where the <somewhere> is a java installations that you've added the 3d
extensions to, then that would (I think) explain what's going wrong. That
could happen if you have a JRE installed (without the 3d stuff) earlier on your
classpath than the JDK (with the 3d stuff) -- in that case "javac" would find
the right compiler, but "java" would find the wrong java runtime.

-- chris

[tony_l...@yahoo.com]

Thanks. I tried typing:

rakta:~$ type java
java is /usr/bin/java

so /usr is a java installation. You mean that JRE (without the 3d
stuff) and JDK (with the 3d stuff) were installed in the different path?

[tony_l...@yahoo.com]

Chris, you are right. Actually in this computer JRE (without the 3D
stuff) was installed earlier by someone whom I do not know, then I
istall the java3D. I guess that in this case "java" found the wrong
java runtime. So should I reintall the whole JDK, JRE and java3D? I
even do not know how to disinstall all these stuff...
Tony

[Chris Uppal]

tony_l...@yahoo.com wrote:

> Chris, you are right. Actually in this computer JRE (without the 3D
> stuff) was installed earlier by someone whom I do not know, then I
> istall the java3D. I guess that in this case "java" found the wrong
> java runtime. So should I reintall the whole JDK, JRE and java3D?

Bit late now, but FWIW, I would either add the 3s stuff to the "earlier" JRE
(if it's a late enough release of Java that you are happy to use it) or change
my $PATH and so on to exclude it from my environment.

I don't have any real experience of Java on Unix-like systems, but I've never
yet seen Unix system where the software installation wasn't a complete mess. I
generally find it easier (at least in the short term) to side-step the mess
than fix it.

-- chris

[tony_l...@yahoo.com]

So I have to distall all java JRE and SDK, then install them and java3D
again?
But how to distall java JRE and SKD? which command?
Thanks!

[Chris Uppal]

Personally, I'd just leave them in place and ensure that my $PATH (as well as
any Java-specific environment variables) did not point to the installations I
didn't want to use.

If you don't know what the $PATH is, or how to set enviroment variables, then
that's rather too big a topic for a newsgroup posting (especially in a Java
ng), and I suggest you get a good introductory book on Unix and/or Linux.

-- chris