Generating a UID
When we need a unique identifier we can use the UID class found in the java.rmi.server package. This class will generate an identifier that is unique to the host it is generated on. The generated UID is unique under the following conditions:

• the machine takes more than one second to reboot
• the machine's clock is never set backward

For example it is perfect for use within servlets to create a unique id for a visitor.

The following line of code shows an example on how to use this class:

  String uid = new java.rmi.server.UID().toString();