title: What does this class declaration mean in Java?
body: <p>I just learn up to tree and one thing I don't understand about it is the class declaration:</p>
  
  <p>for example: class <code>BinarySearchTree&lt;T extends Comparable&lt;? super T&gt;&gt;</code>. </p>
  
  <p>Now, can you please explain me what is in the bracket and the "<code>&lt;? super T&gt;</code>"?</p>
  
  <p>Any good source you can refer me to? Thanks.</p>