title: Use Case : Collection.singletonList Vs Collection.unmodifiableList
body: <p>As I aware that both Collection methods provides read-only access to returned list and throws Exception on modification.</p>
  
  <p>I need to understand Use Cases of both so that when to use singletonList and unmodifiableList. </p>
  
  <p>This might help me to grow understanding of both based on their usage.</p>