"Property Sets" are a new addition to ADF Business Components (ADF BC) in JDeveloper 11g. Property Sets are related to the extensible Custom Properties framework definable on EO & VO attributes, as well as at the EO, VO and & AM levels. If you're not familiar with the power and usage of ADF Business Component extensible Custom Properties look at my previous post I rest my case: Converting ADF BC EO/VO attributes to upper and lower case with custom properties or Avrom Roy-Faderman's post The Power of Properties.
Property Sets allow us to define a set of Custom Properties, essentially key value pairs, and then apply them to the ADF BC objects, without having to manually create each key value pair manually ourselves.
If we take a rather simplistic example, we could define a new Property Set "Alpha", with 2 properties "Beta" and "Charlie" as follows:
Then for example, we can select an attribute out of an EO or VO, and change the Property Set value to our new Property Set:
To prove the Custom Properties apply at runtime, without coding, within the Business Components Browser, we can right click on the attribute in question, and you can see a small information box that shows the runtime properties of the field, including the Property Set key value pairs we created.
This is obviously just a small new feature within JDeveloper 11g, but yet again a declarative productivity booster to stop the programmer having to waste time inputing values.