docs: private static ZipFileHandle getZipFileHandle(String path) throws IOException {
          synchronized ( zipFileHandlesLock ) {
              ZipFileHandle handle = zipFileHandles.get(path);
              if ( handle == null ) {
                  handle = new ZipFileHandleImpl(path);
                  zipFileHandles.put(path, handle);
              }
              return handle;
          }
      }