--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.graphio/src/org/graalvm/graphio/GraphProtocol.java	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.graphio/src/org/graalvm/graphio/GraphProtocol.java	Thu Oct 17 20:53:35 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 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
@@ -28,6 +28,7 @@
 import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.channels.WritableByteChannel;
 import java.nio.charset.Charset;
@@ -86,6 +87,13 @@
     final int versionMinor;
     private boolean printing;
 
+    /**
+     * See {@code org.graalvm.compiler.serviceprovider.BufferUtil}.
+     */
+    private static Buffer asBaseBuffer(Buffer obj) {
+        return obj;
+    }
+
     GraphProtocol(WritableByteChannel channel, int major, int minor, boolean embedded) throws IOException {
         if (major > MAJOR_VERSION || (major == MAJOR_VERSION && minor > MINOR_VERSION)) {
             throw new IllegalArgumentException("Unrecognized version " + major + "." + minor);
@@ -328,7 +336,7 @@
     }
 
     private void flush() throws IOException {
-        buffer.flip();
+        asBaseBuffer(buffer).flip();
         /*
          * Try not to let interrupted threads abort the write. There's still a race here but an
          * interrupt that's been pending for a long time shouldn't stop this writing.
@@ -411,12 +419,12 @@
         while (b.position() < limit) {
             int toWrite = Math.min(limit - b.position(), buffer.capacity());
             ensureAvailable(toWrite);
-            b.limit(b.position() + toWrite);
+            asBaseBuffer(b).limit(b.position() + toWrite);
             try {
                 buffer.put(b);
                 written += toWrite;
             } finally {
-                b.limit(limit);
+                asBaseBuffer(b).limit(limit);
             }
         }
         return written;
@@ -430,7 +438,7 @@
             int sizeInBytes = b.length * 4;
             ensureAvailable(sizeInBytes);
             buffer.asIntBuffer().put(b);
-            buffer.position(buffer.position() + sizeInBytes);
+            asBaseBuffer(buffer).position(buffer.position() + sizeInBytes);
         }
     }
 
@@ -442,7 +450,7 @@
             int sizeInBytes = b.length * 8;
             ensureAvailable(sizeInBytes);
             buffer.asDoubleBuffer().put(b);
-            buffer.position(buffer.position() + sizeInBytes);
+            asBaseBuffer(buffer).position(buffer.position() + sizeInBytes);
         }
     }