title: What is a Java ClassLoader?
body: <p>In a few simple sentences, what is a Java ClassLoader, when is it used and why?</p>
  
  <p>OK, I read a wiki article. ClassLoader loads classes. OK. So if I include jar files and import, a ClassLoader does the job.</p>
  
  <p>Why should I bother with this ClassLoader? I've never used it and didn't know it existed.</p>
  
  <p>The question is, why does the ClassLoader class exist? And also, how do you use it in practice? (Cases exist, I know.)</p>