have a method which returns an object containing a list. if the list is only one element long the JSON drops the '[' ']' which confuses our client software.

@GET
@Path("list")
@Produces("application/json")
public Three findThreeList()

{ One one = new One(); one.setFirst("previous"); List<One> ones = new ArrayList<One>(1); ones.add(one); Three three = new Three(); three.setOnes(ones); log.info(three); return three; }

generated output without brackets:
{"three":{"ones":

{"first":"previous"}

}}

if multi items in list it's correct:
{"three":{"ones":[

{"first":"previous"}

,

{"first":"next"}

]}}