Properties are sorted within an expector using the order in which the relevant get()-methods appear in the array Java returns when getClass().getMethods() is call. This is essentially arbitrary: it's set by the compiler. USUALLY this order is the order in which the methods appear in your Java file.
This is a feature which has been asked for in the past, and it'd probably be good if I provided some support for arranging them at an object level (perhaps with some special per-object method). There might be a way to hack SimpleInspector to sort the properties, but its display order is pretty closely tied to the property order.
For the time being, I'd move the get()-methods in your Java file so that they appear in the order you'd like them to appear in the inspector, recompile, and see what happens.