After several chapters focused on the realization of a complete system using the Java
EE 7 platform, this chapter has allowed us to take a break and try to review some
key concepts that we were using. Thus, we learned to make our own annotations and
link layers of n-tier applications. In the next chapter, we will continue with the imple-
mentation of our application by integrating, this time, the validation of data exchanged
between the different layers.