title: createStatement method in jdbc
body: <p>I have learned that Connection is an interface and we can define only method definition in interface.
    So how does this work:</p>
  
  <p>....</p>
  
  <p>Statement stmt = con.createStatement();</p>
  
  <p>....</p>
  
  <p>How does this method create a Statement object and return it?</p>