This Bugzilla instance is a read-only archive of historic NetBeans bug reports. To report a bug in NetBeans please follow the project's instructions for reporting issues.
If you start two instances of NetBeans on one computer, both uses same port number. When bundled tomcat is started it should checked whether desired port is free and in case it isn't user should be informed or another free port should be used.
It could be solved in similar way as in AppServer plugin.
Seems to be fixed. 1) There is no no bundled tomcat anymore. 2) Message appears when port is already used. Closing as fixed.