I’m using Eclipse Europa, which also has the Favorite preference section:
Window > Preferences > Java > Editor > Content Assist > Favorites
In mine, I have the following entries (when adding, use “New Type” and omit the .*):
org.hamcrest.Matchers.*
org.hamcrest.CoreMatchers.*
org.junit.*
org.junit.Assert.*
org.junit.Assume.*
org.junit.matchers.JUnitMatchers.*
All but the third of those are static imports. By having those as favorites, if I type “assertT” and hit Ctrl+Space, Eclipse offers up assertThat as a suggestion, and if I pick it, it will add the proper static import to the file.