--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/classes/java/util/concurrent/Exchanger.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed under the
+ * Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0. 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and 
+ * limitations under the License.
+ */
+
+package java.util.concurrent;
+
+/**
+ * model class for java.util.concurrent.Exchanger
+ * We model because the original class goes to great lengths implementing
+ * memory based synchronization, using execution time and spins
+ * 
+ * Exchangers are also per se shared objects, so we want to minimize field
+ * access from bytecode
+ */
+public class Exchanger<V> {
+  
+  // created on native side and pinned down until transaction is complete
+  static class Exchange<T> {
+    Thread waiterThread;
+    boolean waiterTimedOut;
+    
+    T waiterData;
+    T responderData;
+  }
+  
+  //-- only accessed from native methods
+  private Exchange<V> exchange;
+  
+  
+  public native V exchange(V value) throws InterruptedException;
+
+  private native V exchange0 (V value, long timeoutMillis) throws InterruptedException, TimeoutException;
+  
+  // unfortunately we can't directly go native here without duplicating the TimeUnit conversion in the peer
+  public V exchange(V value, long timeout, TimeUnit unit) throws InterruptedException, TimeoutException {
+    long to = unit.convert(timeout,TimeUnit.MILLISECONDS);
+    return exchange0( value, to);
+  }
+}