title: What is difference between IList and IList<T>
body: <p>Definition of <code>List&lt;T&gt;</code> in .net shows it implement various interfaces. </p>
  
  <pre><code>public class List&lt;T&gt; : IList&lt;T&gt;, ICollection&lt;T&gt;, IEnumerable&lt;T&gt;, IList, ICollection, IEnumerable
  </code></pre>
  
  <p>What changes interfaces with and without <code>T</code> brings in <code>IList</code> i.e. if one of my class implement <code>IList&lt;T&gt;</code> and not <code>IList</code>, then can I use it as my custom collection class or not?</p>