JNI classloading in WLS8.1

Question

Hi,
I have a web app that contains a class that uses a (3rd party) c library via JNI.
This works fine until the web app is redeployed, when I get an exception stating
that the library has already been loaded be another class loader.
From my research I understand that to get round this, I need to include the class
that loads the c lib in the System CLASSPATH, as opposed to the java.class.path.
OK, I can add an entry to the CLASSPATH, but since the class itself is deep in
the web app's .war file, how do I exclude it from the java.class.path?
Alternatively, is there a way to UN-load the library - ideally automatically,
during a redeployment?
TIA
Paul

Answer 1

I've had the same error, and the only thing BEA could say to do was remove the
library from your WAR, and put it somewhere else that is on the system CLASSPATH.
This will prevent the duplication of JNI loading.
It's a hack, but if you have to do it, you have to.
"Paul" <[email protected]> wrote:
>
Hi,
I have a web app that contains a class that uses a (3rd party) c library
via JNI.
This works fine until the web app is redeployed, when I get an exception
stating
that the library has already been loaded be another class loader.
From my research I understand that to get round this, I need to include
the class
that loads the c lib in the System CLASSPATH, as opposed to the java.class.path.
OK, I can add an entry to the CLASSPATH, but since the class itself is
deep in
the web app's .war file, how do I exclude it from the java.class.path?
Alternatively, is there a way to UN-load the library - ideally automatically,
during a redeployment?
TIA
Paul