--- /dev/null	2019-02-27 18:10:44.000000000 -0800
+++ new/src/java.base/share/classes/java/lang/IterableOnce.java	2019-02-27 18:10:44.000000000 -0800
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2019, 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.lang;
+
+import java.util.Iterator;
+
+/**
+ * An Iterable from which only a single Iterator can be obtained.
+ *
+ * @apiNote
+ * IterableOnce is functionally identical to Iterable. A class can
+ * implement IterableOnce in preference to Iterable in order to signal
+ * to applications that only a single Iterator can be obtained. It is
+ * recommended that attempts to call the iterator() method the second
+ * and subsequent time results in IllegalStateException.
+ *
+ * @param <T> the type of elements returned by the iterator
+ */
+public interface IterableOnce<T> extends Iterable<T> {
+    /**
+     * Returns an iterator over elements of type {@code T}. This method
+     * can be called successfully only once. The second and subsequent
+     * invocations of this method throw IllegalStateException.
+     *
+     * @return an Iterator
+     * @throws IllegalStateException if this method has been called previously
+     */
+    Iterator<T> iterator();
+}