Jsp - jar - dll

Question

Hi,
I'm using eclipse to develope a java application.
There is a dll that located in my Java project.
I have a class that uses this dll.
I createf a jar file out of this Java project.
When creating the Jar, there is a "jar file specification" window, in which we choose all of the files we want to be included in the jar. I selected there also that dll file that one of the classes has to use. The jar, as you cas understand, has to contain the dll file and knows how to use it.
My goal is to invoke a method in the jar thru jsp file. The jar is located in the "lib" folder of a web application. (also developed by eclipse).
Basically, the jar is running Ok being called thru the jsp.
The problem occures when the jsp call a method in the jar file, while this method is initializing an instance of a class that uses that dll (the dll I told about above).
jsp - > jar's method - > new class that uses the dll - > Exception
The dll's name if HASPJava, and the exception I get is:
java.lang.UnsatisfiedLinkError: no HASPJava in java.library.path
I inserted the HASPJava.dll into the "lib" folder in the web project, so that the jsp file should recognize it, but maybe I have to do it in another way. Maybe in the class path or something... maybe in the manifest of the jar...
Thanks for any advice.

Answer 1

sarcasteak wrote:
You need to add the dll file to the jar's manifest so it knows how to find it, otherwise it will assume it is at the root of the jar file.I'm sorry, but that's completley wrong. DLLs containing native code have to be on the path of the application, i.e. java.exe (in this case the java running Tomcat). You can add an extra path by specifiying -Djava.library.path as a VM arg when java is started.
Putting DLLs in jar files just won't work as the OS can't look inside jar files