Classes used by the Java backend, particularly in the implementation

Estimated hours taken: 10.

Classes used by the Java backend, particularly in the implementation
of RTTI.

java/Compare.java:
java/Unify.java:
 	New files.  Java classes for implementation of wrapper classes
	around the builtin `unify'and `compare' predicates.

java/JavaInternal.java:
 	New file.  Java class for storing runtime information such
	as command line arguments.

java/DuExistInfo.java:
java/DuExistLocn.java:
java/DuFunctorDesc.java:
java/DuPtagLayout.java:
java/EnumFunctorDesc.java:
java/NotagFunctorDesc.java:
java/ProcAddr.java:
java/PseudoTypeInfo.java:
java/Sectag_Locn.java:
java/TypeCtorInfo_Struct.java
java/TypeCtorRep.java:
java/TypeFunctors.java:
java/TypeLayout.java:
 	New files.  Java classes for implementing Mercury RTTI.

java/UnreachableDefault.java:
 	New file.  Runtime exception that signals that unreachable
	default case in a switch statement has been reached.

runtime/mercury_type_info.h:
	Update comments to mention that Java runtime classes will
	need to be altered if structures in this file are.

java/JavaInternal.java

@@ -0,0 +1,20 @@
+//
+// Copyright (C) 2001 The University of Melbourne.
+// This file may only be copied under the terms of the GNU Library General
+// Public License - see the file COPYING.LIB in the Mercury distribution.
+//
+//
+// All modifications to this file will require changes to:
+// compiler/mlds_to_java.m
+// 
+//
+// At the moment this class is just used to store the command line
+//   arguments.  We can't put them in one of the library modules because
+//   we need to hold them in a class variable in a top level class.   
+//
+
+package mercury.runtime;
+
+public class JavaInternal {
+	public static java.lang.String[] args;
+}