If you have ever programmed using Java IO, you will quickly run into a situation in which a class creates data on an OutputStream and you need to send it to another class that expects to read the data from an input stream. You'll soon be asking the question, "How do I convert an OutputStream to an InputStream?"
Nowhere in Java will you find a OutpStreamToInputStreamConverter class. Luckily, there are several ways to go about this.