Calling C++ DLL's Using JNI

I have a question.. I need to call few C++ DLL methods from java. So I planned use JNI to do that. The question is there any probable or known performance issues if tried to call DLL's from java application. And also I also appreciate If you can you please send me a link where I can find a sample code for running DLL's using Java application
Note: I know I dont have any control on performance issues with DLL's

look at http://staff.develop.com/halloway/code/jawin.html

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Calling C++ DLL's Using JNI

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