由于jasper报告，需要重新启动Tomcat

I am using Jasper reports in my application for generating reports. I have also provided the facility to download the reports in Pdf/Csv format. But the problem I am facing is that, whenever I upload a new war file (with or without the changes in the JRXML files used for designing the reports) I have to start/stop the tomcat server. Unless I do that, I am not able to generate the reports. There are no logs seen nothing happens and the reports are not generated as well. As soon as I restart the server, everything starts working like a charm. Reports get generated and everything else is fine. Why is this so? Why do I have to restart the server every time I upload a new war file? And this is a random behaviour. Its not always necessary to restart the server the moment new war file is uploaded, it may be required to restart the server after some time. (But it has to be restarted once in the new war's lifetime) Is there any bug in Jasper reports regarding this behaviour? How can I avoid this server-restart issue?I am using Jasper reports in my application for