Recently we observed JVM crashes on one of our UI servers that we traced back the XLS emitter, triggered by downloads from the list tab. A user was apparently trying to download more data from the list tab than the emitter could handle.
Investigation showed that in this environment, the system property webclient.maxdownloadrows had not been set.
We set this property to 1000 to limit the size of the recordset and the issue was resovled.