As Josh mentioned in "This Week in Spring" already, Eugen Paraschiv recently did a noteworthy survey on the adoption of Spring 4 and Java 8 as well as Spring Boot: http://www.baeldung.com/java-8-spring-4-and-spring-boot-adoption

Those are interesting numbers for us. Within the Spring universe, Java 8 adoption seems to be approaching 40%! And in terms of Spring Framework versions, Spring 4 is at 65% already, which I'm really happy to see. Even taking into account that a large part of the corporate use of Spring might not be represented in those numbers, that's a great trend. And Pivotal's early production support for Spring 4 on JDK 8 certainly helped in the corporate world as well.

It's equally great to see that a third of the responders are using Spring Boot in the meantime. In other words, half of the Spring 4 userbase is also using Spring Boot, which is impressive for such a young project. Spring Boot's immediate inclusion in our Spring I/O Platform with full production support last year might have boosted its adoption quite a bit. But even more importantly, it simply seems to be a fit for today's application development challenges...