Hi all, I want to compare all elements in the collection with other element of the same collection. In my case I have collection of Segment, a Segment contains startDate and endDate. The whole collection of Segment should consists on complete calendar year and every segment in the list must start 1+ from the endDate of last element. Valid fact should be: MemberShip Segment 1: StartDate: 01-01-2010 EndDate: 30-05-2010 Segment 2: StartDate: 31-05-2010 EndDate: 08-08-2010 Segment 3: StartDate 09-08-2010 EndDate: 31-12-1020 Data structure class Segment{ java.util.Date startDate; java.util.Date endDate; } class Membership{ java.util.ArrayList<Segment> segments; } I know the date functions. I just want to know how can I traverse the List from get element on Index and Index+1? -- View this message in context: http://n3.nabble.com/How-to-traverse-the-Collection-by-index-tp434756p434... Sent from the Drools - User mailing list archive at Nabble.com.