--- a/src/java.base/share/classes/java/io/Reader.java	Wed Dec 06 11:43:50 2017 -0800
+++ b/src/java.base/share/classes/java/io/Reader.java	Wed Dec 06 14:39:15 2017 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2017, 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
@@ -26,6 +26,8 @@
 package java.io;
 
 
+import java.util.Objects;
+
 /**
  * Abstract class for reading character streams.  The only methods that a
  * subclass must implement are read(char[], int, int) and close().  Most
@@ -50,6 +52,8 @@
 
 public abstract class Reader implements Readable, Closeable {
 
+    private static final int TRANSFER_BUFFER_SIZE = 8192;
+
     /**
      * The object used to synchronize operations on this stream.  For
      * efficiency, a character-stream object may use an object other than
@@ -262,4 +266,41 @@
      */
      public abstract void close() throws IOException;
 
+    /**
+     * Reads all characters from this reader and writes the characters to the
+     * given writer in the order that they are read. On return, this reader
+     * will be at end of the stream. This method does not close either reader
+     * or writer.
+     * <p>
+     * This method may block indefinitely reading from the reader, or
+     * writing to the writer. The behavior for the case where the reader
+     * and/or writer is <i>asynchronously closed</i>, or the thread
+     * interrupted during the transfer, is highly reader and writer
+     * specific, and therefore not specified.
+     * <p>
+     * If an I/O error occurs reading from the reader or writing to the
+     * writer, then it may do so after some characters have been read or
+     * written. Consequently the reader may not be at end of the stream and
+     * one, or both, streams may be in an inconsistent state. It is strongly
+     * recommended that both streams be promptly closed if an I/O error occurs.
+     *
+     * @param  out the writer, non-null
+     * @return the number of characters transferred
+     * @throws IOException if an I/O error occurs when reading or writing
+     * @throws NullPointerException if {@code out} is {@code null}
+     *
+     * @since 10
+     */
+    public long transferTo(Writer out) throws IOException {
+        Objects.requireNonNull(out, "out");
+        long transferred = 0;
+        char[] buffer = new char[TRANSFER_BUFFER_SIZE];
+        int nRead;
+        while ((nRead = read(buffer, 0, TRANSFER_BUFFER_SIZE)) >= 0) {
+            out.write(buffer, 0, nRead);
+            transferred += nRead;
+        }
+        return transferred;
+    }
+
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/io/Reader/TransferTo.java	Wed Dec 06 14:39:15 2017 -0800
@@ -0,0 +1,353 @@
+/*
+ * Copyright (c) 2017, 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 source 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 source 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 Franklsource 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.
+ */
+
+import java.io.*;
+import java.util.Arrays;
+import java.util.Random;
+
+import jdk.test.lib.RandomFactory;
+
+import static java.lang.String.format;
+
+/*
+ * @test
+ * @bug 8191706
+ * @summary tests whether java.io.Reader.transferTo conforms to its
+ *          contract defined source the javadoc
+ * @library /test/lib
+ * @build jdk.test.lib.RandomFactory
+ * @run main TransferTo
+ * @key randomness
+ * @author Patrick Reinhart
+ */
+public class TransferTo {
+
+    private static Random generator = RandomFactory.getRandom();
+
+    public static void main(String[] args) throws IOException {
+        ifOutIsNullThenNpeIsThrown();
+        ifExceptionInInputNeitherStreamIsClosed();
+        ifExceptionInOutputNeitherStreamIsClosed();
+        onReturnNeitherStreamIsClosed();
+        onReturnInputIsAtEnd();
+        contents();
+    }
+
+    private static void ifOutIsNullThenNpeIsThrown() throws IOException {
+        try (Reader in = input()) {
+            assertThrowsNPE(() -> in.transferTo(null), "out");
+        }
+
+        try (Reader in = input((char) 1)) {
+            assertThrowsNPE(() -> in.transferTo(null), "out");
+        }
+
+        try (Reader in = input((char) 1, (char) 2)) {
+            assertThrowsNPE(() -> in.transferTo(null), "out");
+        }
+
+        Reader in = null;
+        try {
+            Reader fin = in = new ThrowingReader();
+            // null check should precede everything else:
+            // Reader shouldn't be touched if Writer is null
+            assertThrowsNPE(() -> fin.transferTo(null), "out");
+        } finally {
+            if (in != null)
+                try {
+                    in.close();
+                } catch (IOException ignored) { }
+        }
+    }
+
+    private static void ifExceptionInInputNeitherStreamIsClosed()
+            throws IOException {
+        transferToThenCheckIfAnyClosed(input(0, new char[]{1, 2, 3}), output());
+        transferToThenCheckIfAnyClosed(input(1, new char[]{1, 2, 3}), output());
+        transferToThenCheckIfAnyClosed(input(2, new char[]{1, 2, 3}), output());
+    }
+
+    private static void ifExceptionInOutputNeitherStreamIsClosed()
+            throws IOException {
+        transferToThenCheckIfAnyClosed(input(new char[]{1, 2, 3}), output(0));
+        transferToThenCheckIfAnyClosed(input(new char[]{1, 2, 3}), output(1));
+        transferToThenCheckIfAnyClosed(input(new char[]{1, 2, 3}), output(2));
+    }
+
+    private static void transferToThenCheckIfAnyClosed(Reader input,
+                                                       Writer output)
+            throws IOException {
+        try (CloseLoggingReader in = new CloseLoggingReader(input);
+             CloseLoggingWriter out =
+                     new CloseLoggingWriter(output)) {
+            boolean thrown = false;
+            try {
+                in.transferTo(out);
+            } catch (IOException ignored) {
+                thrown = true;
+            }
+            if (!thrown)
+                throw new AssertionError();
+
+            if (in.wasClosed() || out.wasClosed()) {
+                throw new AssertionError();
+            }
+        }
+    }
+
+    private static void onReturnNeitherStreamIsClosed()
+            throws IOException {
+        try (CloseLoggingReader in =
+                     new CloseLoggingReader(input(new char[]{1, 2, 3}));
+             CloseLoggingWriter out =
+                     new CloseLoggingWriter(output())) {
+
+            in.transferTo(out);
+
+            if (in.wasClosed() || out.wasClosed()) {
+                throw new AssertionError();
+            }
+        }
+    }
+
+    private static void onReturnInputIsAtEnd() throws IOException {
+        try (Reader in = input(new char[]{1, 2, 3});
+             Writer out = output()) {
+
+            in.transferTo(out);
+
+            if (in.read() != -1) {
+                throw new AssertionError();
+            }
+        }
+    }
+
+    private static void contents() throws IOException {
+        checkTransferredContents(new char[0]);
+        checkTransferredContents(createRandomChars(1024, 4096));
+        // to span through several batches
+        checkTransferredContents(createRandomChars(16384, 16384));
+    }
+
+    private static void checkTransferredContents(char[] chars)
+            throws IOException {
+        try (Reader in = input(chars);
+             StringWriter out = new StringWriter()) {
+            in.transferTo(out);
+
+            char[] outChars = out.toString().toCharArray();
+            if (!Arrays.equals(chars, outChars)) {
+                throw new AssertionError(
+                        format("chars.length=%s, outChars.length=%s",
+                                chars.length, outChars.length));
+            }
+        }
+    }
+
+    private static char[] createRandomChars(int min, int maxRandomAdditive) {
+        char[] chars = new char[min + generator.nextInt(maxRandomAdditive)];
+        for (int index=0; index<chars.length; index++) {
+            chars[index] = (char)generator.nextInt();
+        }
+        return chars;
+    }
+
+    private static Writer output() {
+        return output(-1);
+    }
+
+    private static Writer output(int exceptionPosition) {
+        return new Writer() {
+
+            int pos;
+
+            @Override
+            public void write(int b) throws IOException {
+                if (pos++ == exceptionPosition)
+                    throw new IOException();
+            }
+
+            @Override
+            public void write(char[] chars, int off, int len) throws IOException {
+                for (int i=0; i<len; i++) {
+                    write(chars[off + i]);
+                }
+            }
+
+            @Override
+            public Writer append(CharSequence csq, int start, int end) throws IOException {
+                for (int i = start; i < end; i++) {
+                    write(csq.charAt(i));
+                }
+                return this;
+            }
+
+            @Override
+            public void flush() throws IOException {
+            }
+
+            @Override
+            public void close() throws IOException {
+            }
+        };
+    }
+
+    private static Reader input(char... chars) {
+        return input(-1, chars);
+    }
+
+    private static Reader input(int exceptionPosition, char... chars) {
+        return new Reader() {
+
+            int pos;
+
+            @Override
+            public int read() throws IOException {
+                if (pos == exceptionPosition) {
+                    throw new IOException();
+                }
+
+                if (pos >= chars.length)
+                    return -1;
+                return chars[pos++];
+            }
+
+            @Override
+            public int read(char[] cbuf, int off, int len) throws IOException {
+                int c = read();
+                if (c == -1) {
+                    return -1;
+                }
+                cbuf[off] = (char)c;
+
+                int i = 1;
+                for (; i < len ; i++) {
+                    c = read();
+                    if (c == -1) {
+                        break;
+                    }
+                    cbuf[off + i] = (char)c;
+                }
+                return i;
+            }
+
+            @Override
+            public void close() throws IOException {
+            }
+        };
+    }
+
+    private static class ThrowingReader extends Reader {
+
+        boolean closed;
+
+        @Override
+        public int read(char[] b, int off, int len) throws IOException {
+            throw new IOException();
+        }
+
+        @Override
+        public void close() throws IOException {
+            if (!closed) {
+                closed = true;
+                throw new IOException();
+            }
+        }
+        @Override
+        public int read() throws IOException {
+            throw new IOException();
+        }
+    }
+
+    private static class CloseLoggingReader extends FilterReader {
+
+        boolean closed;
+
+        CloseLoggingReader(Reader in) {
+            super(in);
+        }
+
+        @Override
+        public void close() throws IOException {
+            closed = true;
+            super.close();
+        }
+
+        boolean wasClosed() {
+            return closed;
+        }
+    }
+
+    private static class CloseLoggingWriter extends FilterWriter {
+
+        boolean closed;
+
+        CloseLoggingWriter(Writer out) {
+            super(out);
+        }
+
+        @Override
+        public void close() throws IOException {
+            closed = true;
+            super.close();
+        }
+
+        boolean wasClosed() {
+            return closed;
+        }
+    }
+
+    public interface Thrower {
+        public void run() throws Throwable;
+    }
+
+    public static void assertThrowsNPE(Thrower thrower, String message) {
+        assertThrows(thrower, NullPointerException.class, message);
+    }
+
+    public static <T extends Throwable> void assertThrows(Thrower thrower,
+                                                          Class<T> throwable,
+                                                          String message) {
+        Throwable thrown;
+        try {
+            thrower.run();
+            thrown = null;
+        } catch (Throwable caught) {
+            thrown = caught;
+        }
+
+        if (!throwable.isInstance(thrown)) {
+            String caught = thrown == null ?
+                    "nothing" : thrown.getClass().getCanonicalName();
+            throw new AssertionError(
+                    format("Expected to catch %s, but caught %s",
+                            throwable, caught), thrown);
+        }
+
+        if (thrown != null && !message.equals(thrown.getMessage())) {
+            throw new AssertionError(
+                    format("Expected exception message to be '%s', but it's '%s'",
+                            message, thrown.getMessage()));
+        }
+    }
+}