There seem to be a couple of edge cases where the package private accessibility of ErrorPageFilter causes problems in an application. While not necessarily a SpringBoot fault, containers such as Tomcat and JBoss will try and fail to access the class under certain conditions. See http://stackoverflow.com/questions/27189047/springboot-webapp-under-java-securitymanager-throws-exceptions-when-granted-allp and #933 for more info.
It would be helpful if the class could be made public. Thanks.