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A Java interface to SWI Prolog is available using JPL.

JPL is integrated into the full SWI-Prolog distribution starting with version 5.4.x, including binaries for MS-Windows and a Linux RPM. Documentation is -like all integrated packages-, available from the SWI-Prolog website and from the local manual browser under Help/Package documentation. Examples are included in the directory doc/packages/examples/jpl relative to the installation directory. These examples include embedding Prolog in Java as well as the other way around.

JPL is actively maintained by Paul Singleton.