title: How to use org.apache.commons.lang namespace in Java?
body: <p>I tried in <em>Eclipse</em> to use <code>org.apache.commons.lang.NotImplementedException</code>, though it seems from what I can see both from <em>IntelliSense</em> and the <em>Package Explorer</em>, that that namespace does not exist. </p>
  
  <p>So I guess I must load some other package(do you call them libraries in java?) than those it loaded by default.</p>
  
  <p>This is my current setup: (<em>link dead</em>)</p>