Please extract all files from the j-Interop.zip. The "lib" folder has all the jars required to use j-Interop library.
Installation of j-interop.jar is similar to any standard jar file, just add it and it's distribution jars to the classpath.
As a performance improvement, the j-Interop library comes with a
progIdVsClsidDB.properties file, which gets updated with the clsid of each ProgId. This prevents the library from accessing the Windows Registry for the clsid, when the same COM server is required again. Please make sure that
progIdVsClsidDB.properties is also included in the classpath.