Yes,that's my version.
I'm so ashamed for making a misstake that i have changed the DefaultConnectionProvider in my plugin.I have two different mysql database on server,one is the openfire db and another is base db for my own info.when insert ing data to base db i change the DefaultConnectionProvider from openfire db to base db,while creating MultiUserChat room aimed to the openfire db,so it comes the Exception.
I will verify my thought first.thanks all .