code: public synchronized boolean contains(RelativePath path) {
          try {
              checkIndex();
              return getZipIndexEntry(path) != null;
          }
          catch (IOException e) {
              return false;
          }
      }
docs: Tests if a specific path exists in the zip.  This method will return true
  for file entries and directories.
  
  @param path A path within the zip.
  @return True if the path is a file or dir, false otherwise.