--- old/test/demo/zipfs/ZFSTests.java	2018-11-29 12:29:05.863934400 +0530
+++ new/test/demo/zipfs/ZFSTests.java	2018-11-29 12:29:04.846218200 +0530
@@ -22,20 +22,30 @@
  */
 
 /* @test
-   @bug 7156873
-   @summary ZipFileSystem regression tests
+ @bug 7156873 8199776
+ @summary ZipFileSystem regression tests
  */
 
-
+import java.io.IOException;
+import java.io.OutputStream;
 import java.net.URI;
 import java.nio.file.*;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.HashMap;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
 
 public class ZFSTests {
 
     public static void main(String[] args) throws Throwable {
         test7156873();
+        test8199776();
     }
 
     static void test7156873() throws Throwable {
@@ -53,4 +63,112 @@
             Files.deleteIfExists(dir);
         }
     }
+
+    static void test8199776() throws Throwable {
+
+        // root entry "/"
+        Path path = Paths.get("rootdir.zip");
+        URI uri = URI.create("jar:" + path.toUri());
+
+        Set<String> dirs = new HashSet<>();
+        Set<String> files = new HashSet<>();
+        try (OutputStream os = Files.newOutputStream(path);
+                ZipOutputStream zos = new ZipOutputStream(os)) {
+            zos.putNextEntry(new ZipEntry("/"));
+            dirs.add("/");
+            zos.putNextEntry(new ZipEntry("foo"));
+            files.add("/foo");
+            zos.write("/foo".getBytes());
+            zos.putNextEntry(new ZipEntry("bar"));
+            files.add("/bar");
+            zos.write("/bar".getBytes());
+        }
+        AtomicInteger cnt = new AtomicInteger();
+        int max = 3;
+        try (FileSystem fs = FileSystems.newFileSystem(uri,
+                Collections.emptyMap())) {
+            Files.walkFileTree(fs.getRootDirectories().iterator().next(),
+                    new SimpleFileVisitor<Path>() {
+
+                        @Override
+                        public FileVisitResult visitFile(Path file,
+                                BasicFileAttributes attrs) throws IOException {
+                            if (cnt.incrementAndGet() > max)
+                                throw new RuntimeException(
+                                        "visited too many files/dirs");
+                            files.remove(file.toString());
+                            if (!Arrays.equals(Files.readAllBytes(file), file
+                                    .toString().getBytes()))
+                                throw new RuntimeException(
+                                        "visited files has wrong content: "
+                                                + file);
+                            return FileVisitResult.CONTINUE;
+                        }
+
+                        @Override
+                        public FileVisitResult preVisitDirectory(Path dir,
+                                BasicFileAttributes attrs) throws IOException {
+                            if (cnt.incrementAndGet() > max)
+                                throw new RuntimeException(
+                                        "visited too many files/dirs");
+                            dirs.remove(dir.toString());
+                            return FileVisitResult.CONTINUE;
+                        }
+                    });
+            if (cnt.get() != max || dirs.size() != 0 || files.size() != 0)
+                throw new RuntimeException("walk files/dirs failed");
+
+        } finally {
+            Files.deleteIfExists(path);
+        }
+
+        // absolute file/dir, no need to test cnt again..
+        dirs.clear();
+        files.clear();
+        try (OutputStream os = Files.newOutputStream(path);
+                ZipOutputStream zos = new ZipOutputStream(os)) {
+            zos.putNextEntry(new ZipEntry("/"));
+            dirs.add("/");
+            zos.putNextEntry(new ZipEntry("/fooo/"));
+            dirs.add("/fooo/");
+            zos.putNextEntry(new ZipEntry("/foo"));
+            files.add("/foo");
+            zos.write("/foo".getBytes());
+            zos.putNextEntry(new ZipEntry("/bar"));
+            files.add("/bar");
+            zos.write("/bar".getBytes());
+            zos.putNextEntry(new ZipEntry("/fooo/bar"));
+            files.add("/fooo/bar");
+            zos.write("/fooo/bar".getBytes());
+        }
+
+        try (FileSystem fs = FileSystems.newFileSystem(uri,
+                Collections.emptyMap())) {
+            Files.walkFileTree(fs.getRootDirectories().iterator().next(),
+                    new SimpleFileVisitor<Path>() {
+                        @Override
+                        public FileVisitResult visitFile(Path file,
+                                BasicFileAttributes attrs) throws IOException {
+                            files.remove(file.toString());
+                            if (!Arrays.equals(Files.readAllBytes(file), file
+                                    .toString().getBytes()))
+                                throw new RuntimeException(
+                                        "visited files has wrong content: "
+                                                + file);
+                            return FileVisitResult.CONTINUE;
+                        }
+
+                        @Override
+                        public FileVisitResult preVisitDirectory(Path dir,
+                                BasicFileAttributes attrs) throws IOException {
+                            dirs.remove(dir.toString());
+                            return FileVisitResult.CONTINUE;
+                        }
+                    });
+            if (dirs.size() != 0 || files.size() != 0)
+                throw new RuntimeException("walk files/dirs failed");
+        } finally {
+            Files.deleteIfExists(path);
+        }
+    }
 }