That's all folks! Whew! Well that's a ton of information in a comparatively small amount of space. A word of caution/forewarning to the bold ones out there; it's difficult enough getting an application running alone in a language you are just learning. When you throw in an external service to the mix, be it them calling you or you calling them, the difficulty rises exponentially and it's easy to get frustrated/discouraged when things don't work as you expect them to.

Patience is key to learn something well, and even if you were able to run through this entire chapter successfully on the first go, we encourage you to go back and really understand what is going on and try to write your own classes/methods before moving on. The next chapters will build on the ideas explored in this chapter more in depth and moving forward with a shaky understanding that will just leave you confused and annoyed.

The next chapter will explore the interactions with external services that originate from within...