code: private byte[] readContent( ZipInputStream zipInputStream ) throws IOException {
          int bufferLength = 1024;
          byte[] buffer = new byte[bufferLength];
          int n;
          ByteArrayOutputStream baout = new ByteArrayOutputStream();
          while ((n = zipInputStream.read(buffer, 0, bufferLength)) > -1) {
              baout.write(buffer, 0, n);
          }
          return baout.toByteArray();
      }
docs: Reads the content from the {@link ZipInputStream}, making sure it doesn't close the stream.
  
  @param zipInputStream the input stream
  @return the content
  @throws IOException if there is a problem reading the stream