title: Why synchronized method is not included in interface
body: <p>When I use <code>synchronized</code> on a method in an interface, the compiler emits an error. Can you tell me why this happens? </p>
  
  <p>What is the reason (logically) that <code>synchronized</code> cannot be applied to a method on an <code>interface</code>?</p>
  
  <p>I tried to make an Interface over Threadpool <a href="https://stackoverflow.com/questions/14482268/doubts-in-the-code-of-thread-pool-implementation">in this link</a>.
  Help me to make Interface in my above code.</p>