It's been years since I've using Spring. Everybody who pays me to work in Java has used Guava for a while. Most of what I do on my own account is in Python or C (yuck!) or AVR8 assembler. The one Java project I am working on for myself uses balls-to-the-walls metaprogramming and code generation and is designed to enable even more metaprogramming and code generation and doesn't need dependency injection.
I spent a lot of time learning Spring in the day and I felt it filled a gap in Java in a way Guava really doesn't. I call it "configuration driven development". I was writing a large series of report generators in Python and all of them had the structure of "a little script that assembles a few objects in a library together to do a task". In the case of Java that "script" is naturally a Java class that needs to be compiled, goes through the build process, involves artifact management, etc. It's very nice that Spring provides a "general configuration file" that lets you patch together a few objects without having to compile anything.
