During installation using the GUI installer the progress feedback halts at 41% for potentially a long time while the Update Center is bootstrapped. We really need to provide progress feedback during this point of the installation.
The UC Java client (that is doing the downloads) does provide the ability to register a progress tracker. In UC 2.3.4 this progress tracker will be used to provide better feedback when bootstrapping via the CLI. We should also leverage this to provide better feedback during installation using the GUI.
I'm not sure if the installer is invoking the bootstraper via the Java API (in which case adding the tracker should be fairly straightforward) or via System.exec() of java on the bootstrapper jar (in which case we either change the installer to use the API, or get a bit creative). We may need to make a change in UC to allow the passing of a progress tracker via the bootstrap API.
As a side note: 3.1 has a regression where the UC bootstrap phase takes even longer than it did in 3.0.1. This is covered by bug
GLASSFISH-16067 (UC bug UPDATECENTER2-2175). This is being improved in UC 2.3.4.