10.20.8 The Jasper Library

The Jasper library module is the Prolog interface to the Java VM. It corresponds to the se.sics.jasper package in Java. It is loaded by executing the query:

| ?- use_module(library(jasper)).

The Jasper library fully supports multiple SICStus runtimes in a process.

Jasper cannot be used when the SICStus runtime is statically linked to the executable, such as when using spld --static.

The following functionality is provided:

• Initializing the Java VM using the JNI Invocation API (jasper_initialize/[1,2], jasper_deinitialize/1).
• Creating and deleting Java objects directly from Prolog (jasper_new_object/5).
• Method calls (jasper_call/4).
• Global and local (object) reference management (jasper_create_global_ref/3, jasper_delete_global_ref/2, jasper_delete_local_ref/2). Global references are used to prevent the JVM from garbage collecting a Java object referenced from Prolog.
• There is also a subdirectory containing example programs (library('jasper/examples')).