How to add java to CageFS

If you would like to make java available from inside CageFS, perform the following steps:

1. Create /etc/cagefs/conf.d/java.cfg and add proper binary files to it:

$ vi /etc/cagefs/conf.d/java.cfg

[java-custom]
comment=Java-custom
paths=/usr/bin/java, /etc/alternatives/java

2. Update skeleton and remount all:

$ cagefsctl --force-update
$ cagefsctl --remount-all