I especially like the tabs in the window on the right, and am trying to find out more about it:
The basis of this application is the cismap client development API. That's based on OGC-WMS, which "provides a simple HTTP interface for requesting geo-registered map images from one or more distributed geospatial databases". The cismap client development API comes with a set of powerful widgets and frameworks enabling developers to enhance Java applications with full OGC-WMS feature editor capabilities.
Hopefully an interview with the developers behind this application (and they have others on the NetBeans Platform) will be published on netbeans.dzone.com soon!