--- old/src/java.base/unix/classes/sun/nio/fs/UnixCopyFile.java	2018-06-04 11:39:59.000000000 -0700
+++ new/src/java.base/unix/classes/sun/nio/fs/UnixCopyFile.java	2018-06-04 11:39:59.000000000 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2018, 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
@@ -373,6 +373,22 @@
         }
     }
 
+    // throw a DirectoryNotEmpty exception if appropriate
+    static void ensureEmptyDir(UnixPath dir) throws IOException {
+        try {
+            long ptr = opendir(dir);
+            try (UnixDirectoryStream stream =
+                new UnixDirectoryStream(dir, ptr, e -> true)) {
+                if (stream.iterator().hasNext()) {
+                    throw new DirectoryNotEmptyException(
+                        dir.getPathForExceptionMessage());
+                }
+            }
+        } catch (UnixException e) {
+            e.rethrowAsIOException(dir);
+        }
+    }
+
     // move file from source to target
     static void move(UnixPath source, UnixPath target, CopyOption... options)
         throws IOException
@@ -465,6 +481,7 @@
 
         // copy source to target
         if (sourceAttrs.isDirectory()) {
+            ensureEmptyDir(source);
             copyDirectory(source, sourceAttrs, target, flags);
         } else {
             if (sourceAttrs.isSymbolicLink()) {