diff --git a/mozilla/extensions/java/xpcom/Makefile.in b/mozilla/extensions/java/xpcom/Makefile.in
index cbab8691ef2..314eb4badbd 100644
--- a/mozilla/extensions/java/xpcom/Makefile.in
+++ b/mozilla/extensions/java/xpcom/Makefile.in
@@ -15,7 +15,7 @@
 #
 # The Initial Developer of the Original Code is
 # IBM Corporation.
-# Portions created by the Initial Developer are Copyright (C) 2004
+# Portions created by the Initial Developer are Copyright (C) 2005
 # IBM Corporation. All Rights Reserved.
 #
 # Contributor(s):
@@ -76,6 +76,10 @@ JAVA_SRCS = \
 		AppFileLocProvider.java \
 		$(NULL)
 
+GEN_JAVA_SRCS = \
+		XPCOMError.java \
+		$(NULL)
+
 LOCAL_INCLUDES	= -I$(JAVA_INCLUDE_PATH)
 
 ifeq ($(OS_ARCH),WINNT)
@@ -96,6 +100,10 @@ EXTRA_DSO_LDOPTS = \
 
 include $(topsrcdir)/config/rules.mk
 
-export::
-	@$(INSTALL) -m 644 $(addprefix $(srcdir)/,$(JAVA_SRCS)) $(JAVA_DIST_DIR)/org/mozilla/xpcom
+XPCOMError.java: $(topsrcdir)/xpcom/base/nsError.h gen-nsError.pl Makefile Makefile.in
+	$(PERL) $(srcdir)/gen-nsError.pl < $< > $@
+
+export:: $(GEN_JAVA_SRCS)
+	@$(INSTALL) -m 644 $(addprefix $(srcdir)/,$(JAVA_SRCS)) $(JAVA_DIST_DIR)/org/mozilla/xpcom
+	@$(INSTALL) -m 644 $(GEN_JAVA_SRCS) $(JAVA_DIST_DIR)/org/mozilla/xpcom
 
diff --git a/mozilla/extensions/java/xpcom/XPCOM.java b/mozilla/extensions/java/xpcom/XPCOM.java
index d5b2e2113a8..1519e6e14e0 100644
--- a/mozilla/extensions/java/xpcom/XPCOM.java
+++ b/mozilla/extensions/java/xpcom/XPCOM.java
@@ -15,7 +15,7 @@
  *
  * The Initial Developer of the Original Code is
  * IBM Corporation.
- * Portions created by the Initial Developer are Copyright (C) 2004
+ * Portions created by the Initial Developer are Copyright (C) 2005
  * IBM Corporation. All Rights Reserved.
  *
  * Contributor(s):
@@ -46,7 +46,7 @@ import java.util.*;
  *  Provides access to methods for initializing XPCOM, as well as helper methods
  *  for working with XPCOM classes.
  */
-public final class XPCOM {
+public final class XPCOM implements XPCOMError {
 
   /**
    * Initializes XPCOM. You must call this method before proceeding
diff --git a/mozilla/extensions/java/xpcom/gen-nsError.pl b/mozilla/extensions/java/xpcom/gen-nsError.pl
new file mode 100644
index 00000000000..15a360e9321
--- /dev/null
+++ b/mozilla/extensions/java/xpcom/gen-nsError.pl
@@ -0,0 +1,157 @@
+#! /usr/bin/env perl
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is Java XPCOM Bindings.
+#
+# The Initial Developer of the Original Code is
+# Michal Ceresna.
+# Portions created by the Initial Developer are Copyright (C) 2005
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#   Michal Ceresna (ceresna@dbai.tuwien.ac.at)
+#   Javier Pedemonte (jhpedemonte@gmail.com)
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either the GNU General Public License Version 2 or later (the "GPL"), or
+# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+# Generates XPCOMError.java from xpcom/base/nsError.h
+#
+# usage: perl gen-nsErrors.pl < <topsrcdir>/xpcom/base/nsError.h > XPCOMError.java
+
+
+print "/* ***** BEGIN LICENSE BLOCK *****\n";
+print " * Version: MPL 1.1/GPL 2.0/LGPL 2.1\n";
+print " *\n";
+print " * The contents of this file are subject to the Mozilla Public License Version\n";
+print " * 1.1 (the \"License\"); you may not use this file except in compliance with\n";
+print " * the License. You may obtain a copy of the License at\n";
+print " * http://www.mozilla.org/MPL/\n";
+print " *\n";
+print " * Software distributed under the License is distributed on an \"AS IS\" basis,\n";
+print " * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License\n";
+print " * for the specific language governing rights and limitations under the\n";
+print " * License.\n";
+print " *\n";
+print " * The Original Code is mozilla.org code.\n";
+print " *\n";
+print " * The Initial Developer of the Original Code is\n";
+print " * Netscape Communications Corporation.\n";
+print " * Portions created by the Initial Developer are Copyright (C) 1998\n";
+print " * the Initial Developer. All Rights Reserved.\n";
+print " *\n";
+print " * Contributor(s):\n";
+print " *\n";
+print " * Alternatively, the contents of this file may be used under the terms of\n";
+print " * either of the GNU General Public License Version 2 or later (the \"GPL\"),\n";
+print " * or the GNU Lesser General Public License Version 2.1 or later (the \"LGPL\"),\n";
+print " * in which case the provisions of the GPL or the LGPL are applicable instead\n";
+print " * of those above. If you wish to allow use of your version of this file only\n";
+print " * under the terms of either the GPL or the LGPL, and not to allow others to\n";
+print " * use your version of this file under the terms of the MPL, indicate your\n";
+print " * decision by deleting the provisions above and replace them with the notice\n";
+print " * and other provisions required by the GPL or the LGPL. If you do not delete\n";
+print " * the provisions above, a recipient may use your version of this file under\n";
+print " * the terms of any one of the MPL, the GPL or the LGPL.\n";
+print " *\n";
+print " * ***** END LICENSE BLOCK ***** */\n";
+
+print "\n";
+print "package org.mozilla.xpcom;\n";
+print "\n\n";
+
+print "/**\n";
+print " * Mozilla error codes.\n";
+print " *\n";
+print " * THIS FILE GENERATED FROM mozilla/xpcom/base/nsError.h.\n";
+print " * PLEASE SEE THAT FILE FOR FULL DOCUMENTATION.\n";
+print " */\n";
+print "public interface XPCOMError {\n";
+
+while (<STDIN>) {
+  $line = $_;
+
+  if ($prevline) {
+    $_ = $prevline.$_;
+  }
+  if (/(.*)\\$/) {
+    #splitted line
+    $prevline = $1;
+    next;
+  }
+  $prevline = "";
+
+  if (/^\s*#define\s+(NS_[A-Z_]+)\s+(0x)?([0-9a-fA-F]+)\s*$/) {
+    #define NS_ERROR_MODULE_XPCOM      1
+    #define NS_ERROR_MODULE_BASE_OFFSET 0x45
+    print "  public static final long $1 = $2$3L;\n";
+  }
+  elsif (/^\s*#define\s+(NS_[A-Z_]+)\s+\((NS_[A-Z_]+)\s+\+\s+(0x)?([0-9a-fA-F]+)\s*\)\s*/) {
+    #define NS_ERROR_NOT_INITIALIZED           (NS_ERROR_BASE + 1)
+    #define NS_ERROR_FACTORY_EXISTS            (NS_ERROR_BASE + 0x100)
+    print "  public static final long $1 = $2 + $3$4L;\n";
+  }
+  elsif (/^\s*#define\s+(NS_[A-Z_]+)\s+\(\(nsresult\)\s*(0x)?([0-9a-fA-F]+)L?\)\s*$/) { 
+    #define NS_ERROR_BASE                      ((nsresult) 0xC1F30000)
+    #define NS_ERROR_ABORT                     ((nsresult) 0x80004004L)
+    print "  public static final long $1 = $2$3L;\n";
+  }
+  elsif (/^\s*#define\s+(NS_[A-Z_]+)\s+NS_ERROR_GENERATE_FAILURE\s*\(\s*(NS_[A-Z_]+)\s*,\s*([0-9]+)\s*\)\s*$/) { 
+    #define NS_BASE_STREAM_CLOSED         NS_ERROR_GENERATE_FAILURE(NS_ERROR_MODULE_BASE, 2)
+    $module = $2;
+    $code = $3;
+    print "  public static final long $1 = ((NS_ERROR_SEVERITY_ERROR<<31) | (($module+NS_ERROR_MODULE_BASE_OFFSET)<<16) | $code);\n";
+  }
+  elsif (/^\s*#define\s+(NS_[A-Z_]+)\s+NS_ERROR_GENERATE_SUCCESS\s*\(\s*(NS_[A-Z_]+)\s*,\s*([0-9]+)\s*\)\s*$/) { 
+    #define NS_SUCCESS_LOSS_OF_INSIGNIFICANT_DATA   NS_ERROR_GENERATE_SUCCESS(NS_ERROR_MODULE_XPCOM,  1)
+    $module = $2;
+    $code = $3;
+    print "  public static final long $1 = ((NS_ERROR_SEVERITY_SUCCESS<<31) | (($module+NS_ERROR_MODULE_BASE_OFFSET)<<16) | $code);\n";
+  }
+  elsif (/^\s*\/\*(.*)\*\/\s*$/ && !/^\s*\/\*@[\{\}]\*\/\s*$/ &&
+         !/^\s*\/\*\ -\*- Mode:/) {
+    #single line comment, but not 
+    #/*@{*/, /*@}*/, 
+    #/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+    print "  /*$1*/\n";
+  }
+  elsif (/^\s*$/) {
+    #empty line, but write only the first
+    #line from a sequence of empty lines
+    if (!$wasEmpty) {
+      print "\n";
+    }
+    $wasEmpty = 1;
+    next;
+  }
+  else {
+    next;
+  }
+
+  $wasEmpty = 0;
+}
+
+print "}\n";
+
diff --git a/mozilla/extensions/java/xpcom/tests/TestArray.java b/mozilla/extensions/java/xpcom/tests/TestArray.java
index 384640845eb..8d6805658cc 100644
--- a/mozilla/extensions/java/xpcom/tests/TestArray.java
+++ b/mozilla/extensions/java/xpcom/tests/TestArray.java
@@ -15,7 +15,7 @@
  *
  * The Initial Developer of the Original Code is
  * IBM Corporation.
- * Portions created by the Initial Developer are Copyright (C) 2004
+ * Portions created by the Initial Developer are Copyright (C) 2005
  * IBM Corporation. All Rights Reserved.
  *
  * Contributor(s):
@@ -120,7 +120,11 @@ public class TestArray {
                            assertEqual(index, expectedIndex[count]));
       } while (true);
     } catch (XPCOMException e) {
-      // array.indexOf() did not find the element
+      // If array.indexOf() did not find the element, it returns
+      // NS_ERROR_FAILURE.
+      if (e.errorcode != XPCOM.NS_ERROR_FAILURE) {
+        throw e;
+      }
     }
 
     index = lastIndexOf(array, foo);