Sometimes, it becomes necessary to “flush” the compiled JSPs that AEM uses internally. In older versions of AEM, you could delete the CRX paths where the JSPs were stored and AEM would rebuild them on the first request.
This changed in AEM 6.1, when the FSClassLoader was added. While in theory, you could go to the filesystem and delete the JSPs there, there’s a much more convenient interface inside the Felix Web Console, at /system/console/slingjsp. You can either visit it in your browser and push the sole button found there, or you can speak directly to the service with curl, like this:
curl -u admin:admin -X POST 'http://localhost:4502/system/console/slingjsp'