I'm trying to implement a sorted list as a simple exercise in Java. To make it generic I have an `add(Comparable obj)` so I can use it with any class that implements the Comparable interface. But, when I use `obj.compareTo(...)` anywhere in the code I get `"unchecked call to compareTo(T) as a member of the raw type java.lang.Comparable"` from the compiler (with `-Xlint:unchecked` option). The code works just fine but I can't figure out how to get rid of that annoying message. Any hints?