title: How to make sure that there is just one instance of class in JVM?
body: <p>I am developing a design pattern, and I want to make sure that here is just one instance of a class in Java Virtual Machine, to funnel all requests for some resource through a single point, but I don't know if it is possible.</p>
  
  <p>I can only think of a way to count instances of a class and destroy all instance after first is created.</p>
  
  <p>Is this a right approach? If not, is there any other way? </p>