title: What is a unified type system?
body: <p>I've read a <a href="http://en.wikipedia.org/wiki/Comparison_of_Java_and_C_Sharp" rel="noreferrer">comparison of C# and Java</a> and the first thing on the list is "Single-root (unified) type system".</p>
  
  <p>Can you describe what a single-root (unified) type system means?</p>