Annetta: The code for setUserData is pretty straightforward - https://secure-web.cisco.com/1lqRoBXBxwRuc0aEnQ8oFuNN_RlfLRm3bRElxY99tY3A7LUUODhqpt26vNG7UyLJwhj8s8pGGgviqeo5Gf3amV6gWH47RNHTkRWtInCZDvZOM5URhXBeJ4EgPybcY7UWncJ9U-J23T_r9Pi-bS29691ozUuqP1J6R0REBXLrgyjTK9WUjRTCotnav0DIGAG5qMN6qxAUOn3N-fCpY-xb1Og7eYQWrWh5oz5xxX6UTqEAPHh87KICRT30JJWA9Etf8h08JGtXcfaqbpS_KmKfluQfxzyouPW3Nnb7xwIzWMRxiJhqtIcxRSpEZi76lpN7h4c8a_45ivGkv8Z4g7beU6pW9M0mpEsFQY8nIn3FpJRLJJ24NX_OSBXVQgKa2fKw-16DJSlOTEncQa2HotxY3pxBw4cVFj-PaS-UYRmaXwVf43ZvXuUR_h3j4sdZZfSoUfnmfktVrdB-GzQJ0gpwT_g/https%3A%2F%2Fgithub.com%2Feclab%2Fmason%2Fblob%2Fmaster%2Fcontrib%2Fgeomason%2Fsim%2Futil%2Fgeo%2FMasonGeometry.java - and it's just holding on to an Object so anything should work there. However, if that method is giving you a casting error for *Integer *when you expect to be getting an *Indv *back I want to check the rest of the code base to see if anything else is calling setUserData at some point. Regards, Robert Zupko On Thu, Feb 14, 2019 at 12:49 PM Annetta Burger <[log in to unmask]> wrote: > The error is on line: > Indv indv = (Indv)geometry.getUserData(); > > Which brings me back to getUserData() and its return types. It is current > set in the Constructor of object Indv class: > this.getGeometry().setUserData(this); > > Best, > Annetta >