A hallmark of the User-friendly Desktop Internet GIS (uDig) program built with Eclipse is that it can be used as a standalone application or a plugin for existing applications. Details on the uDig project as well as installers can be found at the following website:
Click on Downloads at the preceding website to view the list of versions and installers. At the time of writing, 2.0.0.RC1 is the latest stable version. uDig is supported by Windows, macOS X, and Linux.
In this recipe, we will quickly connect to a PostGIS database and then add a layer to uDig.