This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
the general solution to your original problem is that you would define a Comparator for the TreeMap which is used to compare any two elements (=ArrayList<SampleVO>) of the TreeMap and decides which one should be before or after the other. But nevertheless YOU as a developer have to define what makes your ArrayLists comparable and defines the order when compared with another ArrayList.