--- a/src/java.base/share/native/libzip/Deflater.c	Fri Dec 01 17:06:09 2017 -0800
+++ b/src/java.base/share/native/libzip/Deflater.c	Fri Dec 01 22:04:03 2017 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -164,17 +164,14 @@
         res = deflateParams(strm, level, strategy);
         (*env)->ReleasePrimitiveArrayCritical(env, b, out_buf, 0);
         (*env)->ReleasePrimitiveArrayCritical(env, this_buf, in_buf, 0);
-
         switch (res) {
         case Z_OK:
             (*env)->SetBooleanField(env, this, setParamsID, JNI_FALSE);
+        case Z_BUF_ERROR:
             this_off += this_len - strm->avail_in;
             (*env)->SetIntField(env, this, offID, this_off);
             (*env)->SetIntField(env, this, lenID, strm->avail_in);
             return (jint) (len - strm->avail_out);
-        case Z_BUF_ERROR:
-            (*env)->SetBooleanField(env, this, setParamsID, JNI_FALSE);
-            return 0;
         default:
             JNU_ThrowInternalError(env, strm->msg);
             return 0;
@@ -203,19 +200,17 @@
         res = deflate(strm, finish ? Z_FINISH : flush);
         (*env)->ReleasePrimitiveArrayCritical(env, b, out_buf, 0);
         (*env)->ReleasePrimitiveArrayCritical(env, this_buf, in_buf, 0);
-
         switch (res) {
         case Z_STREAM_END:
             (*env)->SetBooleanField(env, this, finishedID, JNI_TRUE);
             /* fall through */
         case Z_OK:
+        case Z_BUF_ERROR:
             this_off += this_len - strm->avail_in;
             (*env)->SetIntField(env, this, offID, this_off);
             (*env)->SetIntField(env, this, lenID, strm->avail_in);
             return len - strm->avail_out;
-        case Z_BUF_ERROR:
-            return 0;
-            default:
+        default:
             JNU_ThrowInternalError(env, strm->msg);
             return 0;
         }

--- a/src/java.base/share/native/libzip/zlib/deflate.c	Fri Dec 01 17:06:09 2017 -0800
+++ b/src/java.base/share/native/libzip/zlib/deflate.c	Fri Dec 01 22:04:03 2017 -0800
@@ -505,8 +505,6 @@
     s->pending = 0;
     s->pending_out = s->pending_buf;
 
-    s->high_water = 0;      /* reset to its inital value 0 */
-
     if (s->wrap < 0) {
         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
     }
@@ -520,7 +518,7 @@
         s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
 #endif
         adler32(0L, Z_NULL, 0);
-    s->last_flush = Z_NO_FLUSH;
+    s->last_flush = -2;
 
     _tr_init(s);
 
@@ -613,7 +611,7 @@
     func = configuration_table[s->level].func;
 
     if ((strategy != s->strategy || func != configuration_table[level].func) &&
-        s->high_water) {
+        s->last_flush != -2) {
         /* Flush the last buffer: */
         int err = deflate(strm, Z_BLOCK);
         if (err == Z_STREAM_ERROR)

--- a/src/java.base/share/native/libzip/zlib/patches/ChangeLog_java	Fri Dec 01 17:06:09 2017 -0800
+++ b/src/java.base/share/native/libzip/zlib/patches/ChangeLog_java	Fri Dec 01 22:04:03 2017 -0800
@@ -93,4 +93,6 @@
       s->status =
   #ifdef GZIP
 
+(7) deflate.c undo (6), replaced withe the official zlib repo fix see#305/#f969409
+
   

--- a/test/jdk/java/util/zip/InflateIn_DeflateOut.java	Fri Dec 01 17:06:09 2017 -0800
+++ b/test/jdk/java/util/zip/InflateIn_DeflateOut.java	Fri Dec 01 22:04:03 2017 -0800
@@ -23,8 +23,9 @@
 
 /**
  * @test
- * @bug 4206909 4813885
- * @summary Test basic functionality of DeflaterOutputStream/InflaterInputStream and GZIPOutputStream/GZIPInputStream, including flush
+ * @bug 4206909 4813885 8191918
+ * @summary Test basic functionality of DeflaterOutputStream/InflaterInputStream
+ *          and GZIPOutputStream/GZIPInputStream, including flush
  * @key randomness
  */
 
@@ -147,6 +148,36 @@
         check(Arrays.equals(data, buf));
     }
 
+    private static void TestFlushableGZIPOutputStream() throws Throwable {
+        var random = new Random(new Date().getTime());
+
+        var byteOutStream = new ByteArrayOutputStream();
+        var output = new FlushableGZIPOutputStream(byteOutStream);
+
+        var data = new byte[random.nextInt(1024 * 1024)];
+        var buf = new byte[data.length];
+        random.nextBytes(data);
+
+        output.write(data);
+        for (int i=0; i<data.length; i++) {
+            output.write(data[i]);
+        }
+        output.flush();
+        for (int i=0; i<data.length; i++) {
+            output.write(data[i]);
+        }
+        output.write(data);
+        output.close();
+
+        var baos = new ByteArrayOutputStream();
+        try (var gzis = new GZIPInputStream(new
+                ByteArrayInputStream(byteOutStream.toByteArray()))) {
+            gzis.transferTo(baos);
+        }
+        var decompressedBytes = baos.toByteArray();
+        check(decompressedBytes.length == data.length * 4);
+    }
+
     private static void check(InputStream is, OutputStream os)
         throws Throwable
     {
@@ -268,6 +299,7 @@
         LineOrientedProtocol();
         GZWriteFlushRead();
         GZLineOrientedProtocol();
+        TestFlushableGZIPOutputStream();
     }
 
     //--------------------- Infrastructure ---------------------------
@@ -285,3 +317,80 @@
         System.out.println("\nPassed = " + passed + " failed = " + failed);
         if (failed > 0) throw new AssertionError("Some tests failed");}
 }
+
+class FlushableGZIPOutputStream extends GZIPOutputStream {
+    public FlushableGZIPOutputStream(OutputStream os) throws IOException {
+        super(os);
+    }
+
+    private static final byte[] EMPTYBYTEARRAY = new byte[0];
+    private boolean hasData = false;
+
+    /**
+     * Here we make sure we have received data, so that the header has been for
+     * sure written to the output stream already.
+     */
+    @Override
+    public synchronized void write(byte[] bytes, int i, int i1)
+            throws IOException {
+        super.write(bytes, i, i1);
+        hasData = true;
+    }
+
+    @Override
+    public synchronized void write(int i) throws IOException {
+        super.write(i);
+        hasData = true;
+    }
+
+    @Override
+    public synchronized void write(byte[] bytes) throws IOException {
+        super.write(bytes);
+        hasData = true;
+    }
+
+    @Override
+    public synchronized void flush() throws IOException {
+        if (!hasData) {
+            return; // do not allow the gzip header to be flushed on its own
+        }
+
+        // trick the deflater to flush
+        /**
+         * Now this is tricky: We force the Deflater to flush its data by
+         * switching compression level. As yet, a perplexingly simple workaround
+         * for
+         * http://developer.java.sun.com/developer/bugParade/bugs/4255743.html
+         */
+        if (!def.finished()) {
+            def.setInput(EMPTYBYTEARRAY, 0, 0);
+
+            def.setLevel(Deflater.NO_COMPRESSION);
+            deflate();
+
+            def.setLevel(Deflater.DEFAULT_COMPRESSION);
+            deflate();
+
+            out.flush();
+        }
+
+        hasData = false; // no more data to flush
+    }
+
+    /*
+     * Keep on calling deflate until it runs dry. The default implementation
+     * only does it once and can therefore hold onto data when they need to be
+     * flushed out.
+     */
+    @Override
+    protected void deflate() throws IOException {
+        int len;
+        do {
+            len = def.deflate(buf, 0, buf.length);
+            if (len > 0) {
+                out.write(buf, 0, len);
+            }
+        } while (len != 0);
+    }
+
+}