diff --git a/BUCK b/BUCK
index a82bf42..07eb695 100644
--- a/BUCK
+++ b/BUCK
@@ -34,7 +34,11 @@
 
 java_library(
   name = 'lang',
-  srcs = glob([SRC + 'lang/*.java'], excludes = REPL),
+  srcs = glob([
+      SRC + 'exceptions/*.java',
+      SRC + 'lang/*.java',
+    ],
+    excludes = REPL),
 )
 
 java_library(
diff --git a/src/builtin/PRED_$begin_exception_1.java b/src/builtin/PRED_$begin_exception_1.java
index 966e0cd..c4583fe 100644
--- a/src/builtin/PRED_$begin_exception_1.java
+++ b/src/builtin/PRED_$begin_exception_1.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.JavaException;
+import com.googlecode.prolog_cafe.exceptions.PrologException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>'$begin_exception'/1</code><br>
diff --git a/src/builtin/PRED_$call_2.java b/src/builtin/PRED_$call_2.java
index bad81e4..99d960a 100644
--- a/src/builtin/PRED_$call_2.java
+++ b/src/builtin/PRED_$call_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.SystemException;
 import  com.googlecode.prolog_cafe.lang.*;
 import java.lang.reflect.*;
 /**
diff --git a/src/builtin/PRED_$cut_1.java b/src/builtin/PRED_$cut_1.java
index 97aa8eb..ba759e5 100644
--- a/src/builtin/PRED_$cut_1.java
+++ b/src/builtin/PRED_$cut_1.java
@@ -1,4 +1,5 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
  <code>'$cut'/1</code><br>
diff --git a/src/builtin/PRED_$end_exception_1.java b/src/builtin/PRED_$end_exception_1.java
index a73afdb..9793c29 100644
--- a/src/builtin/PRED_$end_exception_1.java
+++ b/src/builtin/PRED_$end_exception_1.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.SystemException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>'$end_exception'/1<code><br>
diff --git a/src/builtin/PRED_$erase_1.java b/src/builtin/PRED_$erase_1.java
index 4416452..5b68f24 100644
--- a/src/builtin/PRED_$erase_1.java
+++ b/src/builtin/PRED_$erase_1.java
@@ -1,4 +1,5 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>'$erase'/1</code><br>
diff --git a/src/builtin/PRED_$fast_write_2.java b/src/builtin/PRED_$fast_write_2.java
index 80b9b45..a86fa8a 100644
--- a/src/builtin/PRED_$fast_write_2.java
+++ b/src/builtin/PRED_$fast_write_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import  com.googlecode.prolog_cafe.lang.*;
 import java.io.PrintWriter;
 /**
diff --git a/src/builtin/PRED_$fast_writeq_2.java b/src/builtin/PRED_$fast_writeq_2.java
index f62f799..7b83a69 100644
--- a/src/builtin/PRED_$fast_writeq_2.java
+++ b/src/builtin/PRED_$fast_writeq_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import  com.googlecode.prolog_cafe.lang.*;
 import java.io.PrintWriter;
 /**
diff --git a/src/builtin/PRED_$get_hash_manager_1.java b/src/builtin/PRED_$get_hash_manager_1.java
index a16ed62..1dbcdd7 100644
--- a/src/builtin/PRED_$get_hash_manager_1.java
+++ b/src/builtin/PRED_$get_hash_manager_1.java
@@ -1,4 +1,5 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
    <code>'$get_hash_manager'/1</code><br>
diff --git a/src/builtin/PRED_$get_instances_2.java b/src/builtin/PRED_$get_instances_2.java
index 9a5f8ee..464daf5 100644
--- a/src/builtin/PRED_$get_instances_2.java
+++ b/src/builtin/PRED_$get_instances_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
    <code>'$get_instances'/2</code><br>
diff --git a/src/builtin/PRED_$hash_adda_3.java b/src/builtin/PRED_$hash_adda_3.java
index 94fea66..f915af6 100644
--- a/src/builtin/PRED_$hash_adda_3.java
+++ b/src/builtin/PRED_$hash_adda_3.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_$hash_addz_3.java b/src/builtin/PRED_$hash_addz_3.java
index ae89ca1..a43d946 100644
--- a/src/builtin/PRED_$hash_addz_3.java
+++ b/src/builtin/PRED_$hash_addz_3.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_$hash_remove_first_3.java b/src/builtin/PRED_$hash_remove_first_3.java
index 4639899..5cf03ec 100644
--- a/src/builtin/PRED_$hash_remove_first_3.java
+++ b/src/builtin/PRED_$hash_remove_first_3.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_$insert_2.java b/src/builtin/PRED_$insert_2.java
index cf07e2b..47186cb 100644
--- a/src/builtin/PRED_$insert_2.java
+++ b/src/builtin/PRED_$insert_2.java
@@ -1,4 +1,5 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
    <code>'$insert'/2</code><br>
diff --git a/src/builtin/PRED_$read_token0_3.java b/src/builtin/PRED_$read_token0_3.java
index 9e4c8bc..f5d473e 100644
--- a/src/builtin/PRED_$read_token0_3.java
+++ b/src/builtin/PRED_$read_token0_3.java
@@ -1,4 +1,9 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.JavaException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import  com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_$statistics_2.java b/src/builtin/PRED_$statistics_2.java
index ab1778f..6d8b75c 100644
--- a/src/builtin/PRED_$statistics_2.java
+++ b/src/builtin/PRED_$statistics_2.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
    <code>'$statistics'/2</code><br>
diff --git a/src/builtin/PRED_$univ_2.java b/src/builtin/PRED_$univ_2.java
index 4483e95..5bad417 100644
--- a/src/builtin/PRED_$univ_2.java
+++ b/src/builtin/PRED_$univ_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
    <code>'$univ'/2</code><br>
diff --git a/src/builtin/PRED_$write_toString_2.java b/src/builtin/PRED_$write_toString_2.java
index 7d7f596..d45fff2 100644
--- a/src/builtin/PRED_$write_toString_2.java
+++ b/src/builtin/PRED_$write_toString_2.java
@@ -1,4 +1,9 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import  com.googlecode.prolog_cafe.lang.*;
 import java.io.PrintWriter;
 /**
diff --git a/src/builtin/PRED_arg_3.java b/src/builtin/PRED_arg_3.java
index 64d8318..ddcdb22 100644
--- a/src/builtin/PRED_arg_3.java
+++ b/src/builtin/PRED_arg_3.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>arg/3</code><br>
diff --git a/src/builtin/PRED_atom_chars_2.java b/src/builtin/PRED_atom_chars_2.java
index 240bde6..ad34f50 100644
--- a/src/builtin/PRED_atom_chars_2.java
+++ b/src/builtin/PRED_atom_chars_2.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>atom_chars/2</code><br>
diff --git a/src/builtin/PRED_atom_codes_2.java b/src/builtin/PRED_atom_codes_2.java
index 19cd473..bbb7bb1 100644
--- a/src/builtin/PRED_atom_codes_2.java
+++ b/src/builtin/PRED_atom_codes_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>atom_codes/2</code><br>
diff --git a/src/builtin/PRED_atom_concat_3.java b/src/builtin/PRED_atom_concat_3.java
index a12d54a..0e1ebda 100644
--- a/src/builtin/PRED_atom_concat_3.java
+++ b/src/builtin/PRED_atom_concat_3.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>atom_concat/3</code><br>
diff --git a/src/builtin/PRED_atom_length_2.java b/src/builtin/PRED_atom_length_2.java
index 390289e..4a45e28 100644
--- a/src/builtin/PRED_atom_length_2.java
+++ b/src/builtin/PRED_atom_length_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>atom_lengt/2</code><br>
diff --git a/src/builtin/PRED_char_code_2.java b/src/builtin/PRED_char_code_2.java
index 5762d2b..a441b02 100644
--- a/src/builtin/PRED_char_code_2.java
+++ b/src/builtin/PRED_char_code_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>char_code/2</code><br>
diff --git a/src/builtin/PRED_close_2.java b/src/builtin/PRED_close_2.java
index 855d9e3..9f9af56 100644
--- a/src/builtin/PRED_close_2.java
+++ b/src/builtin/PRED_close_2.java
@@ -3,21 +3,21 @@
 import java.io.PrintWriter;
 import java.io.PushbackReader;
 
-import com.googlecode.prolog_cafe.lang.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.SystemException;
+import com.googlecode.prolog_cafe.exceptions.TermException;
 import com.googlecode.prolog_cafe.lang.HashtableOfTerm;
-import com.googlecode.prolog_cafe.lang.IllegalDomainException;
-import com.googlecode.prolog_cafe.lang.IllegalTypeException;
 import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
 import com.googlecode.prolog_cafe.lang.ListTerm;
 import com.googlecode.prolog_cafe.lang.Operation;
-import com.googlecode.prolog_cafe.lang.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.Prolog;
 import com.googlecode.prolog_cafe.lang.StructureTerm;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
-import com.googlecode.prolog_cafe.lang.SystemException;
 import com.googlecode.prolog_cafe.lang.Term;
-import com.googlecode.prolog_cafe.lang.TermException;
 /**
  * <code>close/2</code><br>
  * @author Mutsunori Banbara (banbara@kobe-u.ac.jp)
diff --git a/src/builtin/PRED_flush_output_1.java b/src/builtin/PRED_flush_output_1.java
index 3e89d74..41c7909 100644
--- a/src/builtin/PRED_flush_output_1.java
+++ b/src/builtin/PRED_flush_output_1.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.PrintWriter;
 /**
diff --git a/src/builtin/PRED_functor_3.java b/src/builtin/PRED_functor_3.java
index d9b1466..55fd722 100644
--- a/src/builtin/PRED_functor_3.java
+++ b/src/builtin/PRED_functor_3.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>functor/3</code><br>
diff --git a/src/builtin/PRED_get_2.java b/src/builtin/PRED_get_2.java
index b82f122..6ebcd2f 100644
--- a/src/builtin/PRED_get_2.java
+++ b/src/builtin/PRED_get_2.java
@@ -1,4 +1,11 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
+import com.googlecode.prolog_cafe.exceptions.TermException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_get_char_2.java b/src/builtin/PRED_get_char_2.java
index c6509df..538d756 100644
--- a/src/builtin/PRED_get_char_2.java
+++ b/src/builtin/PRED_get_char_2.java
@@ -1,4 +1,11 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
+import com.googlecode.prolog_cafe.exceptions.TermException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_halt_1.java b/src/builtin/PRED_halt_1.java
index 0290a54..da0f691 100644
--- a/src/builtin/PRED_halt_1.java
+++ b/src/builtin/PRED_halt_1.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>halt/1</code><br>
diff --git a/src/builtin/PRED_hash_clear_1.java b/src/builtin/PRED_hash_clear_1.java
index 7c98e53..5c7b437 100644
--- a/src/builtin/PRED_hash_clear_1.java
+++ b/src/builtin/PRED_hash_clear_1.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_hash_contains_key_2.java b/src/builtin/PRED_hash_contains_key_2.java
index b16fafc..dad9c71 100644
--- a/src/builtin/PRED_hash_contains_key_2.java
+++ b/src/builtin/PRED_hash_contains_key_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_hash_get_3.java b/src/builtin/PRED_hash_get_3.java
index ecbfa88..1e01a2f 100644
--- a/src/builtin/PRED_hash_get_3.java
+++ b/src/builtin/PRED_hash_get_3.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_hash_is_empty_1.java b/src/builtin/PRED_hash_is_empty_1.java
index 5e7d1fb..6ba3c8f 100644
--- a/src/builtin/PRED_hash_is_empty_1.java
+++ b/src/builtin/PRED_hash_is_empty_1.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_hash_keys_2.java b/src/builtin/PRED_hash_keys_2.java
index 7d365b7..dfb34c6 100644
--- a/src/builtin/PRED_hash_keys_2.java
+++ b/src/builtin/PRED_hash_keys_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 import java.util.Enumeration;
diff --git a/src/builtin/PRED_hash_put_3.java b/src/builtin/PRED_hash_put_3.java
index e3a47ae..51d73c9 100644
--- a/src/builtin/PRED_hash_put_3.java
+++ b/src/builtin/PRED_hash_put_3.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_hash_remove_2.java b/src/builtin/PRED_hash_remove_2.java
index 1c33571..7ab2613 100644
--- a/src/builtin/PRED_hash_remove_2.java
+++ b/src/builtin/PRED_hash_remove_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_hash_size_2.java b/src/builtin/PRED_hash_size_2.java
index 39e2d63..e1fe6c1 100644
--- a/src/builtin/PRED_hash_size_2.java
+++ b/src/builtin/PRED_hash_size_2.java
@@ -1,4 +1,9 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Hashtable;
 /**
diff --git a/src/builtin/PRED_keysort_2.java b/src/builtin/PRED_keysort_2.java
index abef82f..c2ab4fe 100644
--- a/src/builtin/PRED_keysort_2.java
+++ b/src/builtin/PRED_keysort_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.BuiltinException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.JavaException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Arrays;
 /**
diff --git a/src/builtin/PRED_new_hash_2.java b/src/builtin/PRED_new_hash_2.java
index 8fbbdb3..467458f 100644
--- a/src/builtin/PRED_new_hash_2.java
+++ b/src/builtin/PRED_new_hash_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import com.googlecode.prolog_cafe.lang.*;
 /**
    <code>new_hash/2</code><br>
diff --git a/src/builtin/PRED_number_chars_2.java b/src/builtin/PRED_number_chars_2.java
index 75899c4..56700c4 100644
--- a/src/builtin/PRED_number_chars_2.java
+++ b/src/builtin/PRED_number_chars_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.SyntaxException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>number_chars/2</code><br>
diff --git a/src/builtin/PRED_number_codes_2.java b/src/builtin/PRED_number_codes_2.java
index 0c6437e..c5c6722 100644
--- a/src/builtin/PRED_number_codes_2.java
+++ b/src/builtin/PRED_number_codes_2.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
+import com.googlecode.prolog_cafe.exceptions.SyntaxException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>number_codes/2</code><br>
diff --git a/src/builtin/PRED_open_4.java b/src/builtin/PRED_open_4.java
index 8f3f6ec..3d1b25d 100644
--- a/src/builtin/PRED_open_4.java
+++ b/src/builtin/PRED_open_4.java
@@ -1,4 +1,10 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_put_char_2.java b/src/builtin/PRED_put_char_2.java
index 478b500..950dc29 100644
--- a/src/builtin/PRED_put_char_2.java
+++ b/src/builtin/PRED_put_char_2.java
@@ -1,4 +1,10 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_put_code_2.java b/src/builtin/PRED_put_code_2.java
index d836f6d..4897883 100644
--- a/src/builtin/PRED_put_code_2.java
+++ b/src/builtin/PRED_put_code_2.java
@@ -1,4 +1,10 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_raise_exception_1.java b/src/builtin/PRED_raise_exception_1.java
index 005b5c6..7bd37e7 100644
--- a/src/builtin/PRED_raise_exception_1.java
+++ b/src/builtin/PRED_raise_exception_1.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.TermException;
 import  com.googlecode.prolog_cafe.lang.*;
 /**
  * <code>raise_exception/1</code><br>
diff --git a/src/builtin/PRED_read_line_2.java b/src/builtin/PRED_read_line_2.java
index b13e96f..bc2d2cd 100644
--- a/src/builtin/PRED_read_line_2.java
+++ b/src/builtin/PRED_read_line_2.java
@@ -1,4 +1,10 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.RepresentationException;
+import com.googlecode.prolog_cafe.exceptions.TermException;
 import  com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/builtin/PRED_regex_compile_2.java b/src/builtin/PRED_regex_compile_2.java
index 5c4ef37..26b7509 100644
--- a/src/builtin/PRED_regex_compile_2.java
+++ b/src/builtin/PRED_regex_compile_2.java
@@ -1,8 +1,8 @@
 package com.googlecode.prolog_cafe.builtin;
-import com.googlecode.prolog_cafe.lang.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
 import com.googlecode.prolog_cafe.lang.Operation;
-import com.googlecode.prolog_cafe.lang.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.Prolog;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
diff --git a/src/builtin/PRED_regex_match_3.java b/src/builtin/PRED_regex_match_3.java
index 830d787..0da77c9 100644
--- a/src/builtin/PRED_regex_match_3.java
+++ b/src/builtin/PRED_regex_match_3.java
@@ -1,9 +1,9 @@
 package com.googlecode.prolog_cafe.builtin;
-import com.googlecode.prolog_cafe.lang.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
 import com.googlecode.prolog_cafe.lang.ListTerm;
 import com.googlecode.prolog_cafe.lang.Operation;
-import com.googlecode.prolog_cafe.lang.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.Prolog;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
diff --git a/src/builtin/PRED_sort_2.java b/src/builtin/PRED_sort_2.java
index 162f79f..8325b97 100644
--- a/src/builtin/PRED_sort_2.java
+++ b/src/builtin/PRED_sort_2.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+import com.googlecode.prolog_cafe.exceptions.JavaException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.util.Arrays;
 /**
diff --git a/src/builtin/PRED_tab_2.java b/src/builtin/PRED_tab_2.java
index 65acb2b..ec58a1b 100644
--- a/src/builtin/PRED_tab_2.java
+++ b/src/builtin/PRED_tab_2.java
@@ -1,4 +1,9 @@
 package com.googlecode.prolog_cafe.builtin;
+import com.googlecode.prolog_cafe.exceptions.BuiltinException;
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
 import com.googlecode.prolog_cafe.lang.*;
 import java.io.*;
 /**
diff --git a/src/compiler/Compiler.java b/src/compiler/Compiler.java
index dbc2839..5820745 100644
--- a/src/compiler/Compiler.java
+++ b/src/compiler/Compiler.java
@@ -1,10 +1,10 @@
 package com.googlecode.prolog_cafe.compiler;
+import com.googlecode.prolog_cafe.exceptions.CompileException;
+import com.googlecode.prolog_cafe.exceptions.PrologException;
 import com.googlecode.prolog_cafe.lang.BufferingPrologControl;
-import com.googlecode.prolog_cafe.lang.CompileException;
 import com.googlecode.prolog_cafe.lang.ListTerm;
 import com.googlecode.prolog_cafe.lang.Prolog;
 import com.googlecode.prolog_cafe.lang.PrologClassLoader;
-import com.googlecode.prolog_cafe.lang.PrologException;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
 import com.googlecode.prolog_cafe.lang.Term;
 
diff --git a/src/compiler/am2j/PRED_exists_directory_1.java b/src/compiler/am2j/PRED_exists_directory_1.java
index e655d65..87737f1 100644
--- a/src/compiler/am2j/PRED_exists_directory_1.java
+++ b/src/compiler/am2j/PRED_exists_directory_1.java
@@ -1,11 +1,11 @@
 package com.googlecode.prolog_cafe.compiler.am2j;
 
-import com.googlecode.prolog_cafe.lang.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PrologException;
 import com.googlecode.prolog_cafe.lang.Operation;
-import com.googlecode.prolog_cafe.lang.PInstantiationException;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.Prolog;
-import com.googlecode.prolog_cafe.lang.PrologException;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
 import com.googlecode.prolog_cafe.lang.Term;
 
diff --git a/src/compiler/am2j/PRED_file_directory_name_2.java b/src/compiler/am2j/PRED_file_directory_name_2.java
index 3d255f5..46f00ba 100644
--- a/src/compiler/am2j/PRED_file_directory_name_2.java
+++ b/src/compiler/am2j/PRED_file_directory_name_2.java
@@ -1,12 +1,12 @@
 package com.googlecode.prolog_cafe.compiler.am2j;
 
-import com.googlecode.prolog_cafe.lang.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.PrologException;
 import com.googlecode.prolog_cafe.lang.Operation;
-import com.googlecode.prolog_cafe.lang.PInstantiationException;
-import com.googlecode.prolog_cafe.lang.PermissionException;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.Prolog;
-import com.googlecode.prolog_cafe.lang.PrologException;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
 import com.googlecode.prolog_cafe.lang.Term;
 
diff --git a/src/compiler/am2j/PRED_make_directory_1.java b/src/compiler/am2j/PRED_make_directory_1.java
index 7148696..ed511e3 100644
--- a/src/compiler/am2j/PRED_make_directory_1.java
+++ b/src/compiler/am2j/PRED_make_directory_1.java
@@ -1,12 +1,12 @@
 package com.googlecode.prolog_cafe.compiler.am2j;
 
-import com.googlecode.prolog_cafe.lang.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.PrologException;
 import com.googlecode.prolog_cafe.lang.Operation;
-import com.googlecode.prolog_cafe.lang.PInstantiationException;
-import com.googlecode.prolog_cafe.lang.PermissionException;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.Prolog;
-import com.googlecode.prolog_cafe.lang.PrologException;
 import com.googlecode.prolog_cafe.lang.SymbolTerm;
 import com.googlecode.prolog_cafe.lang.Term;
 
diff --git a/src/compiler/pl2am.pl b/src/compiler/pl2am.pl
index f588822..118d5d1 100644
--- a/src/compiler/pl2am.pl
+++ b/src/compiler/pl2am.pl
@@ -247,8 +247,9 @@
 
 %%% Post-init
 pl2am_postread :- 
-	assert_import('com.googlecode.prolog_cafe.lang'),
 	assert_import('com.googlecode.prolog_cafe.builtin'),
+	assert_import('com.googlecode.prolog_cafe.exceptions'),
+	assert_import('com.googlecode.prolog_cafe.lang'),
 	assert_dummy_package,
 	assert_dummy_public.
 
diff --git a/src/lang/BuiltinException.java b/src/exceptions/BuiltinException.java
similarity index 83%
rename from src/lang/BuiltinException.java
rename to src/exceptions/BuiltinException.java
index 07e44d5..e025454 100644
--- a/src/lang/BuiltinException.java
+++ b/src/exceptions/BuiltinException.java
@@ -1,4 +1,8 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Builtin exception.<br>
  *
diff --git a/src/lang/CompileException.java b/src/exceptions/CompileException.java
similarity index 87%
rename from src/lang/CompileException.java
rename to src/exceptions/CompileException.java
index 6cc899b..9aa9cf4 100644
--- a/src/lang/CompileException.java
+++ b/src/exceptions/CompileException.java
@@ -1,4 +1,4 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
 
 /** Indicates compiling did not succeed. */
 public class CompileException extends Exception {
diff --git a/src/lang/EvaluationException.java b/src/exceptions/EvaluationException.java
similarity index 82%
rename from src/lang/EvaluationException.java
rename to src/exceptions/EvaluationException.java
index f3d8bda..72a07fb 100644
--- a/src/lang/EvaluationException.java
+++ b/src/exceptions/EvaluationException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Evaluation error.<br>
  * There will be an evaluation error when the operands
diff --git a/src/lang/ExistenceException.java b/src/exceptions/ExistenceException.java
similarity index 85%
rename from src/lang/ExistenceException.java
rename to src/exceptions/ExistenceException.java
index 6a7a672..4c1b843 100644
--- a/src/lang/ExistenceException.java
+++ b/src/exceptions/ExistenceException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Existence error.<br>
  * There will be an existence error when the object
diff --git a/src/lang/HaltException.java b/src/exceptions/HaltException.java
similarity index 83%
rename from src/lang/HaltException.java
rename to src/exceptions/HaltException.java
index 5dbd4ef..c10f8e9 100644
--- a/src/lang/HaltException.java
+++ b/src/exceptions/HaltException.java
@@ -1,4 +1,4 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
 
 public class HaltException extends SystemException {
   private final int status;
diff --git a/src/lang/IllegalDomainException.java b/src/exceptions/IllegalDomainException.java
similarity index 86%
rename from src/lang/IllegalDomainException.java
rename to src/exceptions/IllegalDomainException.java
index 7edd75d..c0d72f6 100644
--- a/src/lang/IllegalDomainException.java
+++ b/src/exceptions/IllegalDomainException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Domain error.<br>
  * There will be a domain error when the type of an argument
diff --git a/src/lang/IllegalTypeException.java b/src/exceptions/IllegalTypeException.java
similarity index 84%
rename from src/lang/IllegalTypeException.java
rename to src/exceptions/IllegalTypeException.java
index d6fff68..3ecfe93 100644
--- a/src/lang/IllegalTypeException.java
+++ b/src/exceptions/IllegalTypeException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Type error.<br>
  * There will be a type error when the type of an argument or 
diff --git a/src/lang/InternalException.java b/src/exceptions/InternalException.java
similarity index 83%
rename from src/lang/InternalException.java
rename to src/exceptions/InternalException.java
index ab08b0b..9ce9495 100644
--- a/src/lang/InternalException.java
+++ b/src/exceptions/InternalException.java
@@ -1,4 +1,9 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Internal error.<br>
  *
diff --git a/src/lang/JavaException.java b/src/exceptions/JavaException.java
similarity index 82%
rename from src/lang/JavaException.java
rename to src/exceptions/JavaException.java
index a0f1e2e..6d0b347 100644
--- a/src/lang/JavaException.java
+++ b/src/exceptions/JavaException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Java error.<br>
  * There will be a Java error when 
diff --git a/src/lang/PInstantiationException.java b/src/exceptions/PInstantiationException.java
similarity index 79%
rename from src/lang/PInstantiationException.java
rename to src/exceptions/PInstantiationException.java
index 203d1b3..e190520 100644
--- a/src/lang/PInstantiationException.java
+++ b/src/exceptions/PInstantiationException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Instantiation error.<br>
  * There will be an instantiation error 
diff --git a/src/lang/PermissionException.java b/src/exceptions/PermissionException.java
similarity index 87%
rename from src/lang/PermissionException.java
rename to src/exceptions/PermissionException.java
index c053386..e7ad609 100644
--- a/src/lang/PermissionException.java
+++ b/src/exceptions/PermissionException.java
@@ -1,4 +1,11 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Permission error.<br>
  * There will be a permission error when it is not permitted
diff --git a/src/lang/PrologException.java b/src/exceptions/PrologException.java
similarity index 83%
rename from src/lang/PrologException.java
rename to src/exceptions/PrologException.java
index 0af28c5..cc0cf67 100644
--- a/src/lang/PrologException.java
+++ b/src/exceptions/PrologException.java
@@ -1,4 +1,7 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * The superclass of classes for Prolog exceptions.<br>
  *
diff --git a/src/lang/RepresentationException.java b/src/exceptions/RepresentationException.java
similarity index 82%
rename from src/lang/RepresentationException.java
rename to src/exceptions/RepresentationException.java
index 9f513d6..320f277 100644
--- a/src/lang/RepresentationException.java
+++ b/src/exceptions/RepresentationException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Representation error.<br>
  * There will be a representation error when an implementation
diff --git a/src/lang/SyntaxException.java b/src/exceptions/SyntaxException.java
similarity index 84%
rename from src/lang/SyntaxException.java
rename to src/exceptions/SyntaxException.java
index 2d22ce3..8912f34 100644
--- a/src/lang/SyntaxException.java
+++ b/src/exceptions/SyntaxException.java
@@ -1,4 +1,12 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * Syntax error.<br>
  * There will be a syntax error when a sequence of characters
diff --git a/src/lang/SystemException.java b/src/exceptions/SystemException.java
similarity index 83%
rename from src/lang/SystemException.java
rename to src/exceptions/SystemException.java
index 788b2db..4689a86 100644
--- a/src/lang/SystemException.java
+++ b/src/exceptions/SystemException.java
@@ -1,4 +1,9 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * System error.<br>
  *
diff --git a/src/lang/TermException.java b/src/exceptions/TermException.java
similarity index 87%
rename from src/lang/TermException.java
rename to src/exceptions/TermException.java
index e98db48..b95d4e2 100644
--- a/src/lang/TermException.java
+++ b/src/exceptions/TermException.java
@@ -1,4 +1,7 @@
-package com.googlecode.prolog_cafe.lang;
+package com.googlecode.prolog_cafe.exceptions;
+
+import com.googlecode.prolog_cafe.lang.Term;
+
 /**
  * User-defined exception.<br>
  *
diff --git a/src/lang/Arithmetic.java b/src/lang/Arithmetic.java
index f74591e..a8923f8 100644
--- a/src/lang/Arithmetic.java
+++ b/src/lang/Arithmetic.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.lang;
+
+import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
+import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
+
 /**
  * The <code>Arithmetic</code> class contains a method
  * for evaluating arithmetic expressions.<br>
diff --git a/src/lang/DoubleTerm.java b/src/lang/DoubleTerm.java
index f387213..62c24e8 100644
--- a/src/lang/DoubleTerm.java
+++ b/src/lang/DoubleTerm.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.lang;
+
+import com.googlecode.prolog_cafe.exceptions.EvaluationException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+
 /**
  * Floating point number.
  * The class <code>DoubleTerm</code> wraps a value of 
diff --git a/src/lang/Failure.java b/src/lang/Failure.java
index e8001ae..15c3c04 100644
--- a/src/lang/Failure.java
+++ b/src/lang/Failure.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.lang;
+
+import com.googlecode.prolog_cafe.exceptions.PrologException;
+
 /**
  * Initial backtrak point.<br>
  *
diff --git a/src/lang/IntegerTerm.java b/src/lang/IntegerTerm.java
index 8aebbd8..15a5e4a 100644
--- a/src/lang/IntegerTerm.java
+++ b/src/lang/IntegerTerm.java
@@ -1,4 +1,8 @@
 package com.googlecode.prolog_cafe.lang;
+
+import com.googlecode.prolog_cafe.exceptions.EvaluationException;
+import com.googlecode.prolog_cafe.exceptions.IllegalTypeException;
+
 /**
  * Integer.<br>
  * The class <code>IntegerTerm</code> wraps a value of primitive type 
diff --git a/src/lang/InternalDatabase.java b/src/lang/InternalDatabase.java
index 663383f..cb55888 100644
--- a/src/lang/InternalDatabase.java
+++ b/src/lang/InternalDatabase.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.lang;
+import com.googlecode.prolog_cafe.exceptions.SystemException;
+
 import java.util.LinkedList;
 /**
  * Internal database for dynamic predicates.<br>
diff --git a/src/lang/Operation.java b/src/lang/Operation.java
index 3495b6b..ebe4e41 100644
--- a/src/lang/Operation.java
+++ b/src/lang/Operation.java
@@ -1,5 +1,7 @@
 package com.googlecode.prolog_cafe.lang;
 
+import com.googlecode.prolog_cafe.exceptions.PrologException;
+
 /**
  * Superclass any single step operation in the Prolog interpreter.
  * <p>
diff --git a/src/lang/Prolog.java b/src/lang/Prolog.java
index 23e9755..9b4237e 100644
--- a/src/lang/Prolog.java
+++ b/src/lang/Prolog.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.lang;
+import com.googlecode.prolog_cafe.exceptions.PermissionException;
+import com.googlecode.prolog_cafe.exceptions.SystemException;
+
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.IOException;
diff --git a/src/lang/PrologClassLoader.java b/src/lang/PrologClassLoader.java
index a6625e9..367da97 100644
--- a/src/lang/PrologClassLoader.java
+++ b/src/lang/PrologClassLoader.java
@@ -1,6 +1,9 @@
 package com.googlecode.prolog_cafe.lang;
 
 import static com.googlecode.prolog_cafe.lang.PredicateEncoder.encode;
+
+import com.googlecode.prolog_cafe.exceptions.ExistenceException;
+
 import java.lang.reflect.Constructor;
 import java.util.concurrent.ConcurrentHashMap;
 
diff --git a/src/lang/PrologControl.java b/src/lang/PrologControl.java
index 28dacf5..fe36ef2 100644
--- a/src/lang/PrologControl.java
+++ b/src/lang/PrologControl.java
@@ -1,5 +1,8 @@
 package com.googlecode.prolog_cafe.lang;
 
+import com.googlecode.prolog_cafe.exceptions.HaltException;
+import com.googlecode.prolog_cafe.exceptions.PrologException;
+
 import java.util.Set;
 
 /**
diff --git a/src/lang/StructureTerm.java b/src/lang/StructureTerm.java
index 85a91a6..dd50b01 100644
--- a/src/lang/StructureTerm.java
+++ b/src/lang/StructureTerm.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.lang;
+
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+
 /**
  * Compound term. <br>
  * The <code>StructureTerm</code> class represents a compound term but list.<br>
diff --git a/src/lang/SymbolTerm.java b/src/lang/SymbolTerm.java
index 9a25b34..1725ea6 100644
--- a/src/lang/SymbolTerm.java
+++ b/src/lang/SymbolTerm.java
@@ -1,4 +1,6 @@
 package com.googlecode.prolog_cafe.lang;
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+
 import java.lang.ref.Reference;
 import java.lang.ref.ReferenceQueue;
 import java.lang.ref.WeakReference;
diff --git a/src/lang/VariableTerm.java b/src/lang/VariableTerm.java
index db9f56e..ef28ad4 100644
--- a/src/lang/VariableTerm.java
+++ b/src/lang/VariableTerm.java
@@ -1,4 +1,7 @@
 package com.googlecode.prolog_cafe.lang;
+
+import com.googlecode.prolog_cafe.exceptions.InternalException;
+
 /**
  * Variable.<br>
  * The <code>VariableTerm</code> class represents a logical variable.<br>
diff --git a/src/repl/BlockingPrologControl.java b/src/repl/BlockingPrologControl.java
index c8927c8..829d91d 100644
--- a/src/repl/BlockingPrologControl.java
+++ b/src/repl/BlockingPrologControl.java
@@ -1,9 +1,9 @@
 package com.googlecode.prolog_cafe.repl;
 
+import com.googlecode.prolog_cafe.exceptions.PrologException;
 import com.googlecode.prolog_cafe.lang.HashtableOfTerm;
 import com.googlecode.prolog_cafe.lang.Predicate;
 import com.googlecode.prolog_cafe.lang.PrologControl;
-import com.googlecode.prolog_cafe.lang.PrologException;
 import com.googlecode.prolog_cafe.lang.Term;
 
 /**
diff --git a/src/repl/PrologMain.java b/src/repl/PrologMain.java
index c0d16f6..cb1f0f8 100644
--- a/src/repl/PrologMain.java
+++ b/src/repl/PrologMain.java
@@ -1,5 +1,5 @@
 package com.googlecode.prolog_cafe.repl;
-import com.googlecode.prolog_cafe.lang.HaltException;
+import com.googlecode.prolog_cafe.exceptions.HaltException;
 import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
 import com.googlecode.prolog_cafe.lang.ListTerm;
 import com.googlecode.prolog_cafe.lang.Prolog;