The CAS Development Sandbox VM runs under Oracle Virtualbox (a Yale preferred free VM host) on your desktop or laptop Windows, Mac, or Linux machine. It provides the general setup for using Eclipse to develop an application that will run in JBoss on one or more datacenter VMs. However, it does not try to duplicate the exact setup of datacenter VMs. They are not configured to be friendly for development, and any minor issues that depend on specific directory layouts can be worked out when you deploy to the DEV environment. The Sandbox simplifies the edit, compile, deploy, and debug cycle.
Unlike production systems, which are frequently fixed at old maintenance levels, the Sandbox is typically kept up to date with the latest system, Java, Eclipse, and JBoss patches. At the time this is written, it is a Centos 7 64 bit operating system with Oracle Java 1.7 64 bit, JBoss EAP 6, and Eclipse Luna. You can certainly upgrade Eclipse to the latest release and the minor version numbers of other things don't matter. It is probably a bad idea to use a major version of Java or JBoss other than the ones that will run on the production VMs. Although OpenJDK comes with most Linux distributions, it has a reputation for poor quality control with memory leak problems and is not recommended by either CAS, Eclipse, or JBoss.
There is one user named "casdev" with admin (sudo) privileges. The VM automatically logs on this user and because the VM is not visible outside your host computer there is no security problem.
The Oracle Java comes in a standard "RPM" distribution, so it goes into the directory it is preconfigured to use (/usr/local/java). Eclipse and JBoss are distributed as zip files and could have been installed in many different places. The Sandbox follows one Linux view and puts them in /opt. Generally Eclipse and JBoss are owned by the casdev user and they run interactively under the logged in casdev account.
The VM is a standard Virtualbox 64 bit Linux configuration. With JBoss running the virtual memory use gets up to 1.3 GB, so it could have 1.5 or 2 GB of memory if your laptop is constrained. The Network should be of type "Host-only Adapter". This puts the VM on a virtual Ethernet adapter connected to other VMs and to the host. This virtual private network is assigned IP addresses 192.168.137.*, with the host laptop OS being 192.168.137.1 and the the VMs starting at 192.168.137.10. Generally you can run the Sandbox and a clone of the Sandbox as 10 and 11 on this network.
In order for the VMs to connect to the outside world (to get to the SVN server for example) the host computer must be configured to be a NAT router, forwarding requests from the virtual LAN to the real network adapter. In Windows this type of configuration is called Internet Connection Sharing (ICS). You go to Control Panel - Network and Internet - Network Connections. Right click the real Ethernet adapter (not the VirtualBox Host-Only adapter). Select Properties from the menu. At the top of the dialog there is a Sharing tab. Click the first check box "Allow other users to connect ..." and unclick the second checkbox. Click OK. There will be a large popup warning you (not very clearly) that this is going to change the IPv4 address of the other adapter (the VirtualBox adapter) to 192.168.137.1 and you should only enable sharing if this is OK. That is why this particular subnet address was assigned to the VirtualBox adapter.
If you use a Mac or Linux as your native laptop OS, you are going to have to set up NAT routing yourself.