diff -r 000000000000 -r 212417b74b72 rt/emul/compact/src/main/java/java/util/concurrent/ExecutorCompletionService.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rt/emul/compact/src/main/java/java/util/concurrent/ExecutorCompletionService.java	Sat Mar 19 10:46:31 2016 +0100
@@ -0,0 +1,205 @@
+/*
+ * 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.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+package java.util.concurrent;
+
+/**
+ * A {@link CompletionService} that uses a supplied {@link Executor}
+ * to execute tasks.  This class arranges that submitted tasks are,
+ * upon completion, placed on a queue accessible using {@code take}.
+ * The class is lightweight enough to be suitable for transient use
+ * when processing groups of tasks.
+ *
+ * <p>
+ *
+ * <b>Usage Examples.</b>
+ *
+ * Suppose you have a set of solvers for a certain problem, each
+ * returning a value of some type {@code Result}, and would like to
+ * run them concurrently, processing the results of each of them that
+ * return a non-null value, in some method {@code use(Result r)}. You
+ * could write this as:
+ *
+ * <pre> {@code
+ * void solve(Executor e,
+ *            Collection<Callable<Result>> solvers)
+ *     throws InterruptedException, ExecutionException {
+ *     CompletionService<Result> ecs
+ *         = new ExecutorCompletionService<Result>(e);
+ *     for (Callable<Result> s : solvers)
+ *         ecs.submit(s);
+ *     int n = solvers.size();
+ *     for (int i = 0; i < n; ++i) {
+ *         Result r = ecs.take().get();
+ *         if (r != null)
+ *             use(r);
+ *     }
+ * }}</pre>
+ *
+ * Suppose instead that you would like to use the first non-null result
+ * of the set of tasks, ignoring any that encounter exceptions,
+ * and cancelling all other tasks when the first one is ready:
+ *
+ * <pre> {@code
+ * void solve(Executor e,
+ *            Collection<Callable<Result>> solvers)
+ *     throws InterruptedException {
+ *     CompletionService<Result> ecs
+ *         = new ExecutorCompletionService<Result>(e);
+ *     int n = solvers.size();
+ *     List<Future<Result>> futures
+ *         = new ArrayList<Future<Result>>(n);
+ *     Result result = null;
+ *     try {
+ *         for (Callable<Result> s : solvers)
+ *             futures.add(ecs.submit(s));
+ *         for (int i = 0; i < n; ++i) {
+ *             try {
+ *                 Result r = ecs.take().get();
+ *                 if (r != null) {
+ *                     result = r;
+ *                     break;
+ *                 }
+ *             } catch (ExecutionException ignore) {}
+ *         }
+ *     }
+ *     finally {
+ *         for (Future<Result> f : futures)
+ *             f.cancel(true);
+ *     }
+ *
+ *     if (result != null)
+ *         use(result);
+ * }}</pre>
+ */
+public class ExecutorCompletionService<V> implements CompletionService<V> {
+    private final Executor executor;
+    private final AbstractExecutorService aes;
+    private final BlockingQueue<Future<V>> completionQueue;
+
+    /**
+     * FutureTask extension to enqueue upon completion
+     */
+    private class QueueingFuture extends FutureTask<Void> {
+        QueueingFuture(RunnableFuture<V> task) {
+            super(task, null);
+            this.task = task;
+        }
+        protected void done() { completionQueue.add(task); }
+        private final Future<V> task;
+    }
+
+    private RunnableFuture<V> newTaskFor(Callable<V> task) {
+        if (aes == null)
+            return new FutureTask<V>(task);
+        else
+            return aes.newTaskFor(task);
+    }
+
+    private RunnableFuture<V> newTaskFor(Runnable task, V result) {
+        if (aes == null)
+            return new FutureTask<V>(task, result);
+        else
+            return aes.newTaskFor(task, result);
+    }
+
+    /**
+     * Creates an ExecutorCompletionService using the supplied
+     * executor for base task execution and a
+     * {@link LinkedBlockingQueue} as a completion queue.
+     *
+     * @param executor the executor to use
+     * @throws NullPointerException if executor is {@code null}
+     */
+    public ExecutorCompletionService(Executor executor) {
+        if (executor == null)
+            throw new NullPointerException();
+        this.executor = executor;
+        this.aes = (executor instanceof AbstractExecutorService) ?
+            (AbstractExecutorService) executor : null;
+        this.completionQueue = new LinkedBlockingQueue<Future<V>>();
+    }
+
+    /**
+     * Creates an ExecutorCompletionService using the supplied
+     * executor for base task execution and the supplied queue as its
+     * completion queue.
+     *
+     * @param executor the executor to use
+     * @param completionQueue the queue to use as the completion queue
+     *        normally one dedicated for use by this service. This
+     *        queue is treated as unbounded -- failed attempted
+     *        {@code Queue.add} operations for completed taskes cause
+     *        them not to be retrievable.
+     * @throws NullPointerException if executor or completionQueue are {@code null}
+     */
+    public ExecutorCompletionService(Executor executor,
+                                     BlockingQueue<Future<V>> completionQueue) {
+        if (executor == null || completionQueue == null)
+            throw new NullPointerException();
+        this.executor = executor;
+        this.aes = (executor instanceof AbstractExecutorService) ?
+            (AbstractExecutorService) executor : null;
+        this.completionQueue = completionQueue;
+    }
+
+    public Future<V> submit(Callable<V> task) {
+        if (task == null) throw new NullPointerException();
+        RunnableFuture<V> f = newTaskFor(task);
+        executor.execute(new QueueingFuture(f));
+        return f;
+    }
+
+    public Future<V> submit(Runnable task, V result) {
+        if (task == null) throw new NullPointerException();
+        RunnableFuture<V> f = newTaskFor(task, result);
+        executor.execute(new QueueingFuture(f));
+        return f;
+    }
+
+    public Future<V> take() throws InterruptedException {
+        return completionQueue.take();
+    }
+
+    public Future<V> poll() {
+        return completionQueue.poll();
+    }
+
+    public Future<V> poll(long timeout, TimeUnit unit)
+            throws InterruptedException {
+        return completionQueue.poll(timeout, unit);
+    }
+
+}