diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/java.base/share/classes/java/util/jar/JarOutputStream.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/jar/JarOutputStream.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 1997, 2012, 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.jar;
+
+import java.util.zip.*;
+import java.io.*;
+
+/**
+ * The <code>JarOutputStream</code> class is used to write the contents
+ * of a JAR file to any output stream. It extends the class
+ * <code>java.util.zip.ZipOutputStream</code> with support
+ * for writing an optional <code>Manifest</code> entry. The
+ * <code>Manifest</code> can be used to specify meta-information about
+ * the JAR file and its entries.
+ *
+ * @author  David Connelly
+ * @see     Manifest
+ * @see     java.util.zip.ZipOutputStream
+ * @since   1.2
+ */
+public
+class JarOutputStream extends ZipOutputStream {
+    private static final int JAR_MAGIC = 0xCAFE;
+
+    /**
+     * Creates a new <code>JarOutputStream</code> with the specified
+     * <code>Manifest</code>. The manifest is written as the first
+     * entry to the output stream.
+     *
+     * @param out the actual output stream
+     * @param man the optional <code>Manifest</code>
+     * @exception IOException if an I/O error has occurred
+     */
+    public JarOutputStream(OutputStream out, Manifest man) throws IOException {
+        super(out);
+        if (man == null) {
+            throw new NullPointerException("man");
+        }
+        ZipEntry e = new ZipEntry(JarFile.MANIFEST_NAME);
+        putNextEntry(e);
+        man.write(new BufferedOutputStream(this));
+        closeEntry();
+    }
+
+    /**
+     * Creates a new <code>JarOutputStream</code> with no manifest.
+     * @param out the actual output stream
+     * @exception IOException if an I/O error has occurred
+     */
+    public JarOutputStream(OutputStream out) throws IOException {
+        super(out);
+    }
+
+    /**
+     * Begins writing a new JAR file entry and positions the stream
+     * to the start of the entry data. This method will also close
+     * any previous entry. The default compression method will be
+     * used if no compression method was specified for the entry.
+     * The current time will be used if the entry has no set modification
+     * time.
+     *
+     * @param ze the ZIP/JAR entry to be written
+     * @exception ZipException if a ZIP error has occurred
+     * @exception IOException if an I/O error has occurred
+     */
+    public void putNextEntry(ZipEntry ze) throws IOException {
+        if (firstEntry) {
+            // Make sure that extra field data for first JAR
+            // entry includes JAR magic number id.
+            byte[] edata = ze.getExtra();
+            if (edata == null || !hasMagic(edata)) {
+                if (edata == null) {
+                    edata = new byte[4];
+                } else {
+                    // Prepend magic to existing extra data
+                    byte[] tmp = new byte[edata.length + 4];
+                    System.arraycopy(edata, 0, tmp, 4, edata.length);
+                    edata = tmp;
+                }
+                set16(edata, 0, JAR_MAGIC); // extra field id
+                set16(edata, 2, 0);         // extra field size
+                ze.setExtra(edata);
+            }
+            firstEntry = false;
+        }
+        super.putNextEntry(ze);
+    }
+
+    private boolean firstEntry = true;
+
+    /*
+     * Returns true if specified byte array contains the
+     * jar magic extra field id.
+     */
+    private static boolean hasMagic(byte[] edata) {
+        try {
+            int i = 0;
+            while (i < edata.length) {
+                if (get16(edata, i) == JAR_MAGIC) {
+                    return true;
+                }
+                i += get16(edata, i + 2) + 4;
+            }
+        } catch (ArrayIndexOutOfBoundsException e) {
+            // Invalid extra field data
+        }
+        return false;
+    }
+
+    /*
+     * Fetches unsigned 16-bit value from byte array at specified offset.
+     * The bytes are assumed to be in Intel (little-endian) byte order.
+     */
+    private static int get16(byte[] b, int off) {
+        return Byte.toUnsignedInt(b[off]) | ( Byte.toUnsignedInt(b[off+1]) << 8);
+    }
+
+    /*
+     * Sets 16-bit value at specified offset. The bytes are assumed to
+     * be in Intel (little-endian) byte order.
+     */
+    private static void set16(byte[] b, int off, int value) {
+        b[off+0] = (byte)value;
+        b[off+1] = (byte)(value >> 8);
+    }
+}