How does someone move from sprint to Guava? From what I understand Guava provides nicer collections and utility methods which is not nearly the same thing the Spring ecosystem provides.
Guava is it's own thing with its own problems. In particular I think Guava has proven itself to be very dangerous as a "superdependency" that does too much. Somewhere around Guava 13 they introduced a change that broke HDFS and I was coding for Hadoop at that time and ran into problems w/ diamond dependencies I couldn't bring into my project because they required a Guava that broke my runtime.