title: Multiple Keys to Single Value Map Java
body: <p>I think my question is similar to this one: <a href="https://stackoverflow.com/questions/822322/how-to-implement-a-map-with-multiple-keys">How to implement a Map with multiple keys?</a> but with an important difference. In that question (if my understanding of it is correct, please let me know if it isn't), the keys were supposed to always be unique. I want to have a Map in the form:
  <strong>MyMap</strong> 
  where the keys aren't necessarily unique. If that doesn't make sense, I basically want a 2 dimensional array, but rather than refering to elements by coordinates, I want to refer to them by pairs of objects.</p>
  
  <p>Anyone have any ideas as to either a library where this works or a good way to implement this myself? As far as libraries go, I've looked at Apache Commons and Guava, neither seem to have what I want.</p>