title: Why do we need interfaces when abstract classes exist?
body: <p>One interviewer has asked me the below question and I couldn't answer:</p>
  
  <p>Why do we need Interfaces when abstract classes exist?</p>
  
  <p>Whatever the methods we are writing in interface those we can write in Abstract class also. Then why do we need interfaces separately?</p>
  
  <p>Can anybody please tell what is the reason?</p>
  
  <p>Advance thanks...</p>