Why can't I seem to read an entire compressed

I'm trying to parse Wiktionary dumps on the fly, directly from the URL, in Java. The Wiki dumps are distributed as compressed BZIP2 files, and I am using the following approach to attempt to parse them:

String fileURL = "https://dumps.wikimedia.org/cswiktionary/20171120/cswiktionary-20171120-pages-articles-multistream.xml.bz2";
URL bz2 = new URL(fileURL);
BufferedInputStream bis = new BufferedInputStream(bz2.openStream());
CompressorInputStream input = new CompressorStreamFactory().createCompressorInputStream(bis);
BufferedReader br2 = new BufferedReader(new InputStreamReader(input));
System.out.println(br2.lines().count());

However, the outputted line count is only 36, which is only a fraction of the total file, seeing it's over 20MB in size. Attempting to print the stream line-by-line, only a few lines of XML were actually printed:

String line = br2.readLine();
while(line != null) {
  System.out.println(line);
  line = br2.readLine();
}

Is there something I am missing here? I copied my implementation almost line-for-line from other chunks of code I found online, which others claimed to have worked. Why isn't the entire stream being read? Thanks in advance.

So as it turns out, I was just being dumb. Wiktionary BZIP2 files are explicitly multistream (it even says so in the filename), and as a result, only one stream was being read in using the vanilla Commons Compress classes. You need a multistream reader in order to read multistream files, and from the looks of things, you have to write one yourself. I happened across the following implementation which worked for me:

https://chaosinmotion.blog/2011/07/29/and-another-curiosity-multi-stream-bzip2-files/

Hope this helps someone in the future :)