Accumulate CollectList does not preserve the insertion order ------------------------------------------------------------ Key: DROOLS-519 URL: https://issues.jboss.org/browse/DROOLS-519 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Affects Versions: 6.1.0.Beta4 Reporter: Davide Sottara Assignee: Davide Sottara Priority: Critical In 5.x, acc / collectList preserves the order of insertion. That is, if A1, A2 and A3 are inserted, a collectList will return 1,2,3 In 6.x, the order is reversed. That is, in the same scenario, a list with 3,2,1 is generated. While arguably a minor issue, collectList returns a list, that is an ordered collection. The reversal of the order breaks the compatibility of preexising applications (such as drools-mas)