#vulnerable code 
                              public JimfsPath toRealPath(
      JimfsPath path, PathService pathService, Set<? super LinkOption> options) throws IOException {
    checkNotNull(path);
    checkNotNull(options);

    store.readLock().lock();
    try {
      DirectoryEntry entry = lookUp(path, options)
          .requireExists(path);

      List<Name> names = new ArrayList<>();
      names.add(entry.name());
      while (!entry.file().isRootDirectory()) {
        // entryInParent(), though @Nullable, won't return null here. The only way to get a null
        // entry is to look up a file relative to a SecureDirectoryStream that is open against a
        // deleted directory. toRealPath doesn't do this: it looks up a file relative to a Path,
        // not a SecureDirectoryStream.
        entry = entry.directory().entryInParent();
        names.add(entry.name());
      }

      // names are ordered last to first in the list, so get the reverse view
      List<Name> reversed = Lists.reverse(names);
      Name root = reversed.remove(0);
      return pathService.createPath(root, reversed);
    } finally {
      store.readLock().unlock();
    }
  } 
                            #location 12 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              public JimfsPath toRealPath(
      JimfsPath path, PathService pathService, Set<? super LinkOption> options) throws IOException {
    checkNotNull(path);
    checkNotNull(options);

    store.readLock().lock();
    try {
      DirectoryEntry entry = lookUp(path, options)
          .requireExists(path);

      List<Name> names = new ArrayList<>();
      names.add(entry.name());
      while (!entry.file().isRootDirectory()) {
        entry = entry.directory().entryInParent();
        names.add(entry.name());
      }

      // names are ordered last to first in the list, so get the reverse view
      List<Name> reversed = Lists.reverse(names);
      Name root = reversed.remove(0);
      return pathService.createPath(root, reversed);
    } finally {
      store.readLock().unlock();
    }
  }