front matter
Born as an alternative to EJBs in the early 2000s, the Spring framework quickly overtook its opponent with the simplicity of its programming model, the variety of its features, and its third-party library integrations. The Spring ecosystem grew over the years into the broadest and most mature development framework available in any programming language. Its main competitor quit the race when Oracle stopped the evolution of Java EE 8, and the community took over its maintenance via Jakarta EE.
According to recent surveys (http://mng.bz/l9VB and http://mng.bz/B1Ar), Spring is the framework underlying more than half of the Java applications. This fact builds up an enormous codebase that makes it critical for any Java developer to learn Spring, as it’s inevitable you’ll encounter this technology in your career. I’ve been developing applications with Spring for 15 years, and today the teams that I train in hundreds of companies are almost all using Spring.