title: Implementors of both OutputStream and InputStream for in-memory file transferring
body: <p>I'm using an API (Jasper Reports) to generate PDFs and I'd like to do most of it in memory. I'm already able to get the generated file as an <code>OutputStream</code>, now I'm just looking for an implementor to use to keep things in memory which implements <code>InputStream</code> as well. </p>
  
  <p>What class can I use which functions as both an <code>OutputStream</code> and an <code>InputStream</code> on in-memory data?</p>