Java – how do I get the next key from a specific key in the map?

I have something similar:

Map< Integer,String> topology = new TreeMap< Integer,String>();

These include, for example:

01,my.vm.01.serv.com
04,my.vm.04.serv.com
07,my.vm.07.serv.com
08,my.vm.08.serv.com
09,my.vm.09.serv.com

I want to be able to say "I have key 07. Give me the next key in the map from this point". Ideally, it will return to 08

Is there a way to do this without using iterators?

Solution

If you don't want to change the definition of map, you can try something similar

List<Integer> keys = new ArrayList<Integer>(topology.keySet());
Integer integer = keys.get((keys.indexOf(7))+1); // next key