Hi,

I do heavy Java development and never had issues with OpenJDK on Fedora. And I have OpenJDK on RHEL at many production sites. So don't bother switching to Oracle Java. Instead try unistall and reinstall OpenJDK Packages because it looks you have either a corrupted file.

Other option is you have other Java installations besides the Fedora-provided OpenJDK and you PATH or CLASSPATH have entries for different installations. This happen a lot when you have both GCJ and OpenJDK or Oracle Java and OpenJDK. Maybe you left your browser install Java (from Oracle) instead of configuring the Fedora-provided Java plugin.

Check which java, javac and etc are configured using alternatives and check you env vars. Make sure you are using commands, jars and libraries from the same installation.


[]s, Fernando Lozano


Here a link that explains the java.lang.ClassFormatError:
http://craftingjava.blogspot.co.il/2012/07/reason-for-javalangclassformaterror.html

--------------------
"this error would be thrown when the java virtual machine attempts to read a class file and founds that the class file has been altered in such a way that it loses its integrity."

Here they are trying to say that "if a class file has been modified in a complicated way  then this error would be thrown." 

There may be two possible ways a class file can get corrupted as far i know.

1.May be the compiler have some unresolved bugs in it.
2.The programmer may intentionally change the class file for some reasons.
----------------------

In your case this error does not seem to depend on your code.

So, I can suggest you to use Oracle JDK instead OpenJDK, this because I had some problems using NetBeans and then I got that suggestion, that helped me.


Angelo

On Tue, Jan 27, 2015 at 1:35 AM, Kevin Cummings <cummings@kjchome.homeip.net> wrote:
I updated to java-1.7.0-openjdk.x86_64 1:1.7.0.75-2.5.4.2.fc20 today
(along with the java-1.7.0-openjdk-headless and java-1.7.0-openjdk-devel
packages).  After the upgrade, nothing java related would run.  (not the
compiler, not the jar command, and I couldn't run any pre-built .jars.)
 The error was:

> Error occurred during initialization of VM
> java/lang/ClassFormatError: Unknown constant tag 99 in class file java/lang/Class

Downgrading back to java-1.7.0-openjdk.x86_64 1:1.7.0.60-2.4.3.0.fc20 et
al fixed the problem.

--
Kevin J. Cummings
kjchome@verizon.net
cummings@kjchome.homeip.net
cummings@kjc386.framingham.ma.us
Registered Linux User #1232 (http://www.linuxcounter.net/)
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