Atom is a specialised Term, representing a Prolog atom with the same name.
A Compound represents a structured term, comprising a functor and one or more arguments (Terms).
Float is a specialised Term with a double field, representing a Prolog 64-bit ISO/IEC floating point value.
Integer is a specialised Term representing a Prolog integer value; if the value fits, it is held in a long field, else as a BigInteger.
The jpl.JPL class contains static methods which allow (i) inspection and alteration of the "default" initialisation arguments (ii) explicit initialisation (iii) discovery of whether the Prolog engine is already initialised, and if so, with what arguments.
JRef is a specialised Term with a (non-null, non-String) Object field, representing JPL 7.4's Prolog references to Java objects, e.g.
A Query instance is created by an application in order to query the Prolog database (or to invoke a built-in predicate).
Term is the abstract base class for Compound, Atom, Variable, Integer and Float, which comprise a Java-oriented concrete syntax for Prolog.
This class provides a bunch of static utility methods to support JPL's Java API.
This class supports Java representations of Prolog variables.
This is the base class for exceptions thrown by JPL's Java-calls-Prolog interface.
PrologException instances wrap Prolog exceptions thrown (either by a Prolog engine or by user code) in the course of finding a solution to a Query.