--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.ruby.runtime/src/com/oracle/truffle/ruby/runtime/core/RubyThread.java	Mon Jan 06 17:12:09 2014 +0000
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All rights reserved. This
+ * code is released under a tri EPL/GPL/LGPL license. You can use it,
+ * redistribute it and/or modify it under the terms of the:
+ *
+ * Eclipse Public License version 1.0
+ * GNU General Public License version 2
+ * GNU Lesser General Public License version 2.1
+ */
+package com.oracle.truffle.ruby.runtime.core;
+
+import java.util.*;
+import java.util.concurrent.*;
+
+import com.oracle.truffle.ruby.runtime.objects.*;
+import com.oracle.truffle.ruby.runtime.subsystems.*;
+
+/**
+ * Represents the Ruby {@code Thread} class. Implemented using Java threads, but note that there is
+ * not a one-to-one mapping between Ruby threads and Java threads - specifically in combination with
+ * fibers as they are currently implemented as their own Java threads.
+ */
+public class RubyThread extends RubyObject {
+
+    /**
+     * The class from which we create the object that is {@code Thread}. A subclass of
+     * {@link RubyClass} so that we can override {@link #newInstance} and allocate a
+     * {@link RubyThread} rather than a normal {@link RubyBasicObject}.
+     */
+    public static class RubyThreadClass extends RubyClass {
+
+        public RubyThreadClass(RubyClass objectClass) {
+            super(null, objectClass, "Thread");
+        }
+
+        @Override
+        public RubyBasicObject newInstance() {
+            return new RubyThread(this, getContext().getThreadManager());
+        }
+
+    }
+
+    private final ThreadManager manager;
+
+    private final CountDownLatch finished = new CountDownLatch(1);
+
+    private final int hashCode = new Random().nextInt();
+
+    public RubyThread(RubyClass rubyClass, ThreadManager manager) {
+        super(rubyClass);
+        this.manager = manager;
+    }
+
+    public void initialize(RubyProc block) {
+        final RubyProc finalBlock = block;
+
+        initialize(new Runnable() {
+
+            @Override
+            public void run() {
+                finalBlock.call(null);
+            }
+
+        });
+    }
+
+    public void initialize(Runnable runnable) {
+        final RubyThread finalThread = this;
+        final Runnable finalRunnable = runnable;
+
+        new Thread(new Runnable() {
+
+            @Override
+            public void run() {
+                finalThread.manager.registerThread(finalThread);
+                finalThread.manager.enterGlobalLock(finalThread);
+
+                try {
+                    finalRunnable.run();
+                } finally {
+                    finalThread.manager.leaveGlobalLock();
+                    finalThread.manager.unregisterThread(finalThread);
+                    finalThread.finished.countDown();
+                }
+            }
+
+        }).start();
+    }
+
+    @Override
+    public int hashCode() {
+        return hashCode;
+    }
+
+    public void shutdown() {
+    }
+
+    public void join() {
+        final RubyThread runningThread = getRubyClass().getContext().getThreadManager().leaveGlobalLock();
+
+        try {
+            while (true) {
+                try {
+                    finished.await();
+                    break;
+                } catch (InterruptedException e) {
+                    // Await again
+                }
+            }
+        } finally {
+            runningThread.manager.enterGlobalLock(runningThread);
+        }
+    }
+
+}