This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
In your dispatch method you are passing in a Namelist object called data. How is this Namelist created? Look at how you have implemented this class, make sure it is all working correctly as you are manipulating this in the method, not an ArrayList as you originally stated