public static byte[] compress(byte[] data) {
   ByteArrayInputStream bais = new ByteArrayInputStream(data);
   ByteArrayOutputStream baos = new ByteArrayOutputStream();

   GZipOutputStream gz = new GZipOutputStream(baos);
   copy(bais, gz);
   return baos.toByteArray();
}

public static byte[] decompress(byte[] data) {
   ByteArrayInputStream bais = new ByteArrayInputStream(data);
   ByteArrayOutputStream baos = new ByteArrayOutputStream();

   GZipInputStream gz = new GZipInputStream(baos);
   copy(gz, baos);
   return baos.toByteArray();
}