Look at what you're writing from the client:
saida.write("PAPO");
That doesn't have a line break, so the server doesn't know whether there's more text coming in the same line. Also, because you haven't flushed your writer, it may be that no data is actually being sent. If you just change it to:
saida.write("PAPO\n");
saida.flush();
I suspect you'll find it works.
However, I would strongly recommend that you specify an encoding when using InputStreamReader
and OutputStreamWriter
rather than just using the platform default. UTF-8 is usually a good bet if you control both ends.