The spring could be most popular java framework in this world. It had been born at 2002 which is even earlier than Adobe Flex (dead already). Spring source code provided a very elegant way about how to organize your code and define the Apis. As java developer, all of us should spend time to read source code Spring and get deeply know how to write the solid and high quality code. I am trying to summarize what I got when I review the code and provide a quick guide to understand the code easily. Hope I can finish this giant project. First of all, if we fork the source code from https://github.com/spring-projects/spring-framework it is simple to figoure the modules dep from gradle file. For easy purpose, I draw the diagram to represent the dependencies. The black line is for compile dep and yellow one is for optional dep (just ignore it at very first begging to keep everything simple). Add caption Let's go start from spring-core and spring-beans on the next chapter since