A few places in the RMI API docs, notably in java.rmi.dgc.VMID and java.rmi.server.UID, seem to assume that IP addresses are globally unique and persistent. This might have been the case in the past, where the norm was that addresses were statically allocated. However, in the modern internet, the addresses of a system can change while the system is running, if it changes networks dynamically. In addition, addresses aren't globally unique. For example, many router/firewalls use NAT and will allocate reserved addresses like 192.168.1.* for hosts behind the firewall. Thus, it is quite likely that a host's IP address is not unique at all.

The docs should be reworded to remove mention of IP addresses and instead should discuss general uniqueness requirements.