When getServletContext().getRealPath(System.getProperty("file.separator")) is called in Windows OS, where the file separator is a back slash, the getServletContext().getRealPath("\\") method throws an IllegalArgumentException. It seems to work fine in Tomcat 7.0, but fails in 8.0-RC10. As a temporary workaround solution, I changed the separator to the right slash ("/").
The argument for getRealPath() is a virtual path and should therefore always use "/" as a file separator irrespective of the operating system Tomcat is running on. However, throwing an IllegalArgumentException in this case does not appear to be justified by the Javadoc. getRealPath("\\") should return null.
This has been fixed in 8.0.x and will be included in 8.0.2 onwards.
Restore "Version" field back to 8.0.0-RC10 This issue was reported in 8.0-RC10 and fixed since 8.0.2.