diff --git a/.gitignore b/.gitignore
index 770479e..5fb6938 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 *.gem
 .bundle
 pkg/*
-/benchmark
+/benchmark
\ No newline at end of file
diff --git a/Rakefile b/Rakefile
index 51f8f8b..2f56607 100644
--- a/Rakefile
+++ b/Rakefile
@@ -4,11 +4,17 @@ require 'bundler'
 Bundler::GemHelper.install_tasks
 
 task :clean do
-  rm Dir['lib/ext/**/*.class']
+  rm Dir['ext/java/**/*.class']
 end
 
 task :compile do
-  exec %(javac -source 1.6 -target 1.6 -cp lib/ext/msgpack-0.6.5-SNAPSHOT.jar:$MY_RUBY_HOME/lib/jruby.jar -d lib/ext ext/java/org/msgpack/**/*.java)
+  classpath = (Dir["lib/ext/*.jar"] + ["#{ENV['MY_RUBY_HOME']}/lib/jruby.jar"]).join(':')
+  system %(javac -Xlint:-options -source 1.6 -target 1.6 -cp #{classpath} ext/java/*.java ext/java/org/msgpack/jruby/*.java)
+end
+
+task :package => :compile do
+  class_files = Dir['ext/java/**/*.class'].map { |path| path = path.sub('ext/java/', ''); "-C ext/java '#{path}'" }
+  system %(jar cf lib/ext/msgpack_jruby.jar #{class_files.join(' ')})
 end
 
 namespace :benchmark do
diff --git a/ext/.gitignore b/ext/.gitignore
new file mode 100644
index 0000000..6b468b6
--- /dev/null
+++ b/ext/.gitignore
@@ -0,0 +1 @@
+*.class
diff --git a/ext/java/MsgpackJrubyService.java b/ext/java/MsgpackJrubyService.java
new file mode 100644
index 0000000..ca331ec
--- /dev/null
+++ b/ext/java/MsgpackJrubyService.java
@@ -0,0 +1,15 @@
+import java.io.IOException;
+        
+import org.jruby.Ruby;
+import org.jruby.runtime.load.BasicLibraryService;
+
+import org.msgpack.jruby.MessagePackLibrary;
+
+
+public class MsgpackJrubyService implements BasicLibraryService {
+  public boolean basicLoad(final Ruby runtime) throws IOException {
+    new MessagePackLibrary().load(runtime, false);
+    return true;
+  }
+}
+
diff --git a/ext/java/org/msgpack/jruby/MessagePackLibrary.java b/ext/java/org/msgpack/jruby/MessagePackLibrary.java
new file mode 100644
index 0000000..addd0d2
--- /dev/null
+++ b/ext/java/org/msgpack/jruby/MessagePackLibrary.java
@@ -0,0 +1,68 @@
+package org.msgpack.jruby;
+
+
+import java.io.IOException;
+
+import org.jruby.Ruby;
+import org.jruby.RubyModule;
+import org.jruby.RubyClass;
+import org.jruby.RubyString;
+import org.jruby.runtime.load.Library;
+import org.jruby.runtime.callback.Callback;
+import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.runtime.Arity;
+import org.jruby.runtime.Block;
+
+import org.msgpack.MessagePack;
+import org.msgpack.packer.BufferPacker;
+import org.msgpack.packer.Packer;
+
+
+public class MessagePackLibrary implements Library {
+  public void load(Ruby runtime, boolean wrap) throws IOException {
+    MessagePack msgPack = new MessagePack();
+    RubyModule msgpackModule = runtime.defineModule("MessagePack");
+    msgpackModule.defineModuleFunction("pack", new PackCallback(msgPack));
+    msgpackModule.defineModuleFunction("unpack", new UnpackCallback(msgPack));
+  }
+    
+  private static class PackCallback implements Callback {
+    private MessagePack msgPack;
+    
+    public PackCallback(MessagePack msgPack) {
+      this.msgPack = msgPack;
+    }
+    
+    public IRubyObject execute(IRubyObject recv, IRubyObject[] args, Block block) {
+      try {
+        BufferPacker bufferedPacker = msgPack.createBufferPacker();
+        Packer packer = new RubyObjectPacker(msgPack, bufferedPacker).write(args[0]);
+        return RubyString.newString(recv.getRuntime(), bufferedPacker.toByteArray());
+      } catch (IOException ioe) {
+        // TODO: how to propagate these to the Ruby runtime?
+        return recv.getRuntime().getNil();
+      }
+    }
+    
+    public Arity getArity() { return Arity.ONE_REQUIRED; }
+  }
+
+  private static class UnpackCallback implements Callback {
+    private RubyObjectUnpacker unpacker;
+    
+    public UnpackCallback(MessagePack msgPack) { 
+      this.unpacker = new RubyObjectUnpacker(msgPack);
+    }
+    
+    public IRubyObject execute(IRubyObject recv, IRubyObject[] args, Block block) {
+      try {
+        return unpacker.unpack((RubyString) args[0]);
+      } catch (IOException ioe) {
+        // TODO: how to propagate these to the Ruby runtime?
+        return recv.getRuntime().getNil();
+      }
+    }
+    
+    public Arity getArity() { return Arity.ONE_REQUIRED; }
+  }
+}
\ No newline at end of file
diff --git a/ext/java/org/msgpack/jruby/MessagePackModule.java b/ext/java/org/msgpack/jruby/MessagePackModule.java
deleted file mode 100644
index 286851c..0000000
--- a/ext/java/org/msgpack/jruby/MessagePackModule.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package org.msgpack.jruby;
-
-
-import java.io.IOException;
-
-import org.msgpack.MessagePack;
-import org.msgpack.MessagePack;
-import org.msgpack.packer.BufferPacker;
-
-import org.jruby.Ruby;
-import org.jruby.RubyObject;
-import org.jruby.RubyString;
-import org.jruby.compiler.ir.operands.StandardError;
-
-
-public class MessagePackModule {
-  private static final MessagePack msgPack = new MessagePack();
-  private static final RubyObjectUnpacker unpacker = new RubyObjectUnpacker(msgPack);
-
-  public static RubyString pack(RubyObject o) throws IOException {
-    BufferPacker bufferedPacker = msgPack.createBufferPacker();
-    RubyObjectPacker packer = new RubyObjectPacker(msgPack, bufferedPacker);
-    packer.write(o);
-    Ruby runtime = o == null ? Ruby.getGlobalRuntime() : o.getRuntime();
-    return RubyString.newString(runtime, bufferedPacker.toByteArray());
-  }
-
-  public static RubyObject unpack(RubyString s) throws IOException {
-    return unpacker.unpack(s);
-  }
-
-  public static class Unpacker {
-    public void feed(RubyString s) { }
-  }
-
-  public static class UnpackError extends StandardError { }
-}
diff --git a/ext/java/org/msgpack/jruby/RubyObjectPacker.java b/ext/java/org/msgpack/jruby/RubyObjectPacker.java
index ca01c84..f3d4711 100644
--- a/ext/java/org/msgpack/jruby/RubyObjectPacker.java
+++ b/ext/java/org/msgpack/jruby/RubyObjectPacker.java
@@ -18,6 +18,7 @@
 import org.jruby.RubySymbol;
 import org.jruby.RubyArray;
 import org.jruby.RubyHash;
+import org.jruby.runtime.builtin.IRubyObject;
 
 
 public class RubyObjectPacker extends MessagePackBufferPacker {
@@ -28,7 +29,7 @@ public RubyObjectPacker(MessagePack msgPack, Packer packer) {
     this.packer = packer;
   }
 
-  public Packer write(RubyObject o) throws IOException {
+  public Packer write(IRubyObject o) throws IOException {
     if (o == null || o instanceof RubyNil) {
       packer.writeNil();
       return this;
diff --git a/lib/ext/msgpack_jruby.jar b/lib/ext/msgpack_jruby.jar
new file mode 100644
index 0000000..6210543
Binary files /dev/null and b/lib/ext/msgpack_jruby.jar differ
diff --git a/lib/ext/org/msgpack/jruby/MessagePackModule$UnpackError.class b/lib/ext/org/msgpack/jruby/MessagePackModule$UnpackError.class
deleted file mode 100644
index cc2db05..0000000
Binary files a/lib/ext/org/msgpack/jruby/MessagePackModule$UnpackError.class and /dev/null differ
diff --git a/lib/ext/org/msgpack/jruby/MessagePackModule$Unpacker.class b/lib/ext/org/msgpack/jruby/MessagePackModule$Unpacker.class
deleted file mode 100644
index 9a3b844..0000000
Binary files a/lib/ext/org/msgpack/jruby/MessagePackModule$Unpacker.class and /dev/null differ
diff --git a/lib/ext/org/msgpack/jruby/MessagePackModule.class b/lib/ext/org/msgpack/jruby/MessagePackModule.class
deleted file mode 100644
index 09c3386..0000000
Binary files a/lib/ext/org/msgpack/jruby/MessagePackModule.class and /dev/null differ
diff --git a/lib/ext/org/msgpack/jruby/RubyObjectPacker.class b/lib/ext/org/msgpack/jruby/RubyObjectPacker.class
deleted file mode 100644
index 59b1723..0000000
Binary files a/lib/ext/org/msgpack/jruby/RubyObjectPacker.class and /dev/null differ
diff --git a/lib/ext/org/msgpack/jruby/RubyObjectUnpacker$1.class b/lib/ext/org/msgpack/jruby/RubyObjectUnpacker$1.class
deleted file mode 100644
index d2b1709..0000000
Binary files a/lib/ext/org/msgpack/jruby/RubyObjectUnpacker$1.class and /dev/null differ
diff --git a/lib/ext/org/msgpack/jruby/RubyObjectUnpacker.class b/lib/ext/org/msgpack/jruby/RubyObjectUnpacker.class
deleted file mode 100644
index 2e101f2..0000000
Binary files a/lib/ext/org/msgpack/jruby/RubyObjectUnpacker.class and /dev/null differ
diff --git a/lib/msgpack.rb b/lib/msgpack.rb
index 8b08cb8..15f80a2 100644
--- a/lib/msgpack.rb
+++ b/lib/msgpack.rb
@@ -1,8 +1,8 @@
 # encoding: utf-8
 
-require 'java'
-
-$CLASSPATH << File.expand_path('../ext', __FILE__)
-Dir[File.expand_path('../ext/*.jar', __FILE__)].each { |path| $CLASSPATH << path }
+$: << File.expand_path('../ext', __FILE__)
 
-MessagePack = org.msgpack.jruby.MessagePackModule
+require 'java'
+require 'javassist-3.15.0-GA'
+require 'msgpack-0.6.5-SNAPSHOT'
+require 'msgpack_jruby'
diff --git a/lib/msgpack/unpacker.rb b/lib/msgpack/unpacker.rb
deleted file mode 100644
index 3517866..0000000
--- a/lib/msgpack/unpacker.rb
+++ /dev/null
@@ -1,32 +0,0 @@
-# encoding: ascii-8bit
-
-class MessagePack
-  class Unpacker
-    def initialize
-      @unpacker = org.msgpack.Unpacker.new
-      @type_mapper = org.msgpack.jruby.TypeMapper.new
-    end
-    
-    def feed(bytes)
-      @unpacker.feed(bytes.to_java_bytes)
-    end
-    
-    def each
-      while obj = next_object
-        yield obj
-      end
-    end
-    
-  private
-  
-    def next_object
-      result = @unpacker.next
-      if result.finished?
-        @type_mapper.to_ruby_object(result.data)
-      else
-        nil
-      end
-    end
-  end
-end
-
diff --git a/spec/msgpack/unpacker_spec.rb b/spec/msgpack/unpacker_spec.rb
deleted file mode 100644
index 80369fa..0000000
--- a/spec/msgpack/unpacker_spec.rb
+++ /dev/null
@@ -1,32 +0,0 @@
-# encoding: ascii-8bit
-
-require_relative '../spec_helper'
-
-require 'stringio'
-
-
-describe MessagePack::Unpacker do
-  context 'with a buffer' do
-    it 'unpacks objects fed through #feed' do
-      pending
-      subject.feed(MessagePack.pack('hello' => 'world') + MessagePack.pack('foo' => 42))
-      objects = []
-      subject.each do |obj|
-        objects << obj
-      end
-      objects.should == [{'hello' => 'world'}, {'foo' => 42}]
-    end
-  end
-  
-  context 'with a stream' do
-    it 'unpacks objects from the stream' do
-      pending
-      stream = StringIO.new(MessagePack.pack('hello' => 'world') + MessagePack.pack('foo' => 42))
-      objects = []
-      described_class.new(stream).each do |obj|
-        objects << obj
-      end
-      objects.should == [{'hello' => 'world'}, {'foo' => 42}]
-    end
-  end
-end
\ No newline at end of file