com.google.gwt.core.client.JavaScriptException: (TypeError): Object [object DOMWindow] has no method 'getColumnLabel'

I got this exception for during working on the google table visualization. In fact not only on "getColumnLabel", you will get this exception for all the methods of DataTable. In fact the reason behind is this the DataTable is null or created yet. This somewhat resembles to JAVA null poninter exception. And in GWT you will get this exception from the native lavel. To avoid this first initiate your DataTable and then call the functions.