I have an editable grid created using GWT-EXT which consists of a date column. The date column is editable and the date can be changed using a date picker. When I get the new date , I would like to send it to a grails service so that the corresponding persistent object can be updated. The data rendering on the grid is using JSON and I defined a renderer at the column level so that the display format is what I want. When I change the date, I get the new date in the cell listener. The listener returns the new value as an Object. I create a map with the column name as the key and the new date value as the value and send it to a grails service but the service method does not get called. The same works for all other kinds of objects like Long, Double, String etc. I am using grails 1.1.1, GWT 1.6.4 and GWT-EXT 2.0.5