--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/java/util/stream/Tripwire.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2012, 2013, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 java.util.stream;
+
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+import sun.util.logging.PlatformLogger;
+
+/**
+ * Utility class for detecting inadvertent uses of boxing in
+ * {@code java.util.stream} classes.  The detection is turned on or off based on
+ * whether the system property {@code org.openjdk.java.util.stream.tripwire} is
+ * considered {@code true} according to {@link Boolean#getBoolean(String)}.
+ * This should normally be turned off for production use.
+ *
+ * @apiNote
+ * Typical usage would be for boxing code to do:
+ * <pre>{@code
+ *     if (Tripwire.ENABLED)
+ *         Tripwire.trip(getClass(), "{0} calling Sink.OfInt.accept(Integer)");
+ * }</pre>
+ *
+ * @since 1.8
+ */
+final class Tripwire {
+    private static final String TRIPWIRE_PROPERTY = "org.openjdk.java.util.stream.tripwire";
+
+    /** Should debugging checks be enabled? */
+    static final boolean ENABLED = AccessController.doPrivileged(
+            (PrivilegedAction<Boolean>) () -> Boolean.getBoolean(TRIPWIRE_PROPERTY));
+
+    private Tripwire() { }
+
+    /**
+     * Produces a log warning, using {@code PlatformLogger.getLogger(className)},
+     * using the supplied message.  The class name of {@code trippingClass} will
+     * be used as the first parameter to the message.
+     *
+     * @param trippingClass Name of the class generating the message
+     * @param msg A message format string of the type expected by
+     * {@link PlatformLogger}
+     */
+    static void trip(Class<?> trippingClass, String msg) {
+        PlatformLogger.getLogger(trippingClass.getName()).warning(msg, trippingClass.getName());
+    }
+}