--- a/mx.truffle/suite.py	Mon Jun 22 15:25:07 2015 -0700
+++ b/mx.truffle/suite.py	Tue Jun 23 10:23:10 2015 +0200
@@ -169,7 +169,7 @@
       "subDir" : "truffle",
       "sourceDirs" : ["src"],
       "dependencies" : [
-        "com.oracle.truffle.api",
+        "com.oracle.truffle.api.interop",
         "JUNIT",
       ],
       "checkstyle" : "com.oracle.truffle.dsl.processor",

--- a/truffle/com.oracle.truffle.api.interop/src/com/oracle/truffle/api/interop/ForeignAccess.java	Mon Jun 22 15:25:07 2015 -0700
+++ b/truffle/com.oracle.truffle.api.interop/src/com/oracle/truffle/api/interop/ForeignAccess.java	Tue Jun 23 10:23:10 2015 +0200
@@ -39,9 +39,11 @@
  */
 public final class ForeignAccess {
     private final Factory factory;
+    private final Thread initThread;
 
     private ForeignAccess(Factory faf) {
         this.factory = faf;
+        this.initThread = Thread.currentThread();
     }
 
     /**
@@ -150,11 +152,19 @@
         return (TruffleObject) frame.getArguments()[ForeignAccessArguments.RECEIVER_INDEX];
     }
 
+    private void checkThread() {
+        if (initThread != Thread.currentThread()) {
+            throw new IllegalStateException("ForeignAccess created on " + initThread.getName() + " but used on " + Thread.currentThread().getName());
+        }
+    }
+
     CallTarget access(Message message) {
+        checkThread();
         return factory.accessMessage(message);
     }
 
     boolean canHandle(TruffleObject receiver) {
+        checkThread();
         return factory.canHandle(receiver);
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/interop/ForeignAccessSingleThreadedTest.java	Tue Jun 23 10:23:10 2015 +0200
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api.test.interop;
+
+import com.oracle.truffle.api.CallTarget;
+import com.oracle.truffle.api.interop.ForeignAccess;
+import com.oracle.truffle.api.interop.Message;
+import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.nodes.Node;
+
+import org.junit.*;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class ForeignAccessSingleThreadedTest implements ForeignAccess.Factory, TruffleObject {
+    ForeignAccess fa;
+    private int cnt;
+
+    @Before
+    public void initInDifferentThread() throws InterruptedException {
+        Thread t = new Thread("Initializer") {
+            @Override
+            public void run() {
+                fa = ForeignAccess.create(ForeignAccessSingleThreadedTest.this);
+            }
+        };
+        t.start();
+        t.join();
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void accessNodeFromWrongThread() {
+        Node n = Message.IS_EXECUTABLE.createNode();
+        Object ret = ForeignAccess.execute(n, null, this);
+        fail("Should throw an exception: " + ret);
+    }
+
+    @After
+    public void noCallsToFactory() {
+        assertEquals("No calls to accessMessage or canHandle", 0, cnt);
+    }
+
+    @Override
+    public boolean canHandle(TruffleObject obj) {
+        cnt++;
+        return true;
+    }
+
+    @Override
+    public CallTarget accessMessage(Message tree) {
+        cnt++;
+        return null;
+    }
+
+    @Override
+    public ForeignAccess getForeignAccess() {
+        return fa;
+    }
+}