I agree with PaulHoule. I would add two things. First the focus on and support for testing in Spring is exceptional. Second the Spring Core courses used to be e

I agree with PaulHoule. I would add two things. First the focus on and support for testing in Spring is exceptional. Second the Spring Core courses used to be excellent and done by committers themselves. AFAIK this was outsourced and I don't know how their quality is these days. If you want to have a look at something else you may want to give Dagger 2 a shot. While I think it's a better, more idiomatic, approach to DI for Java you'll quickly become aware how limited it is compared to Spring. I built a small demo app and even for that I said to myself "gee I wish I had X from Spring" available about three times.