Originally from http://article.gmane.org/gmane.comp.java.openjms.user/3170
"A java program connects to OpenJMS and is a durable subscriber to various topics. The java program crashes and the connection to OpenJMS server is lost. When the program is run again and tries to connect to the OpenJMS server it catches an exception that the durable subscriber already exists.
This only happens when a client does not cleanly disconnect form OpenJMS (that is closing all the sessions, topics ..etc)"