code: public static File extractFileGzip(String _compressedFile, String _outputFileName) {
          return decompress(CompressionMethod.GZIP, _compressedFile, _outputFileName);
      }
docs: Extracts a GZIP compressed file to the given outputfile.
  
  @param _compressedFile
  @param _outputFileName
  @return file-object with outputfile or null on any error.