Re: JDK Linux installation help!
On Aug 5, 4:27 pm, "Mike Schilling" <mscottschill...@hotmail.com>
wrote:
cong...@gmail.com wrote:
Hello,
I'm pulling my hair out with the Sun JDK installation on Fedora 7.
Recently, I decided to explore java and downloaded their product,
followed all the directions (used the rpm.bin installation since I'm
to lazy to compile softaware). Downloaded their "HelloWorld" app and
tried to run it and am getting the apparently very common error below:
(did javac HelloWorld.java 1st to creat the HelloWorld.class file)
[congo@localhost java]$ java HelloWorldApp
Exception in thread "main" java.lang.ClassFormatError: HelloWorldApp
(unrecognized class file version)
at java.lang.VMClassLoader.defineClass(libgcj.so.8rh)
at java.lang.ClassLoader.defineClass(libgcj.so.8rh)> at
java.lang.ClassLoader.loadClass(libgcj.so.8rh)
at gnu.java.lang.MainThread.run(libgcj.so.8rh)
All documentation on Sun's website and posts I found in this newsgroup
at java.security.SecureClassLoader.defineClass(libgcj.so.8rh)
at java.net.URLClassLoader.findClass(libgcj.so.8rh)
at gnu.gcj.runtime.SystemClassLoader.findClass(libgcj.so.8rh)
at java.lang.ClassLoader.loadClass(libgcj.so.8rh)
point to updating the CLASSPATH. So I did that in my .bash_profile
file, get the same error. Found the below documentation in the
newsgroup circa 2003:
set JAVA_HOME=/usr/java
set CLASSPATH .;/usr/java/jdk1.6.0_02
export JAVA_HOME CLASSPATH
Did this as root thinking I'd be smart and set the CLASSPATH system
wide even though I'm the only user. At the bottom of that 2003 thread
another guy said that CLASSPATH hasn't been used for years and that I
should just set the PATH in /etc/profile. That's when I stopped and
posted this message. There's a lot of great info/help on how to fix
this problem, but it seems to be taking me further and further into
the forest where I am now lost. Can anyone assist?
My guess is the following:
You installed a recent JDK, and that's where you're running javac from.
There was already a JRE on the machine, and that's where you're running java
from. This JRE is an older version than the JDK you ust installed, so it
can't read the class files that the JDK produces.
You should be able to verify this using "which" (or "whence"). Just ensure
that the java executable you're running comes from the JDK (i.e. from the
same bin directory thata javac lives in), and you shouild be fine.
I think this person is onto something. Sometimes it's possible to get
yourself into a bind when there is a preceding JRE before you install
the one you really want. A few things I'd do in your situation:
which -a java
which -a javac
echo $PATH
java -version
The stacktrace you're getting appears to indicate a version problem
(class files being of a later spec version than what the JVM is able
to run). From what you've said, I gather your current install is
version 1.6.0, which as of now should be able to handle any class
specification. That tells me that when you invoke "java", you're
actually running an older JVM. This could be due to your PATH
pointing to some Fedora's own older JVM perhaps or something that was
on that system previously, maybe a JVM that came with a browser.
Either way, outputting your PATH will let you know how the system is
searching for that executable. "which -a" will tell you all the java
executables it's finding now. Maybe your JAVA_HOME is not being used
as part of PATH. Maybe it's being obscured by this older JVM ghost.