title: How does an Interface in Java work?
body: <p>I'm self learning Java, and I'm stuck on a chapter about Interfaces. I simply cannot understand how they work in Java.</p>
  
  <p>I believe I understand perfectly what Interface means and how they apply in everyday situations and technology. </p>
  
  <p>But when it comes to Java, code-wise and logic-wise, I'm stuck. I don't get it. How does the concept work? </p>
  
  <p>Say I have 3 objects, and 1 interface object. 2 Objects are ObjectCalculatingA, ObjectCalculatingB, ObjectMathFunctions, and ObjectInterface.</p>
  
  <p>Supposedly in ObjectInterface there must be some sort of reference to the ObjectMathFunctions, so that ObjectCalculatingA and B can just access the math functions in ObjectMathFunctions without writting them all again in A and B.</p>
  
  <p>Am I right? </p>