Looking Under the Cover – What is This EE Thing?

Java EE can appear as a magic tool for deployment. However, it is actually just Java code. This chapter intends to look under the cover of the server and ensure that you understand what implications you should expect from the performance of your application. Since covering the entire Java EE space is quite impossible, this chapter will deal with the most common patterns and main specifications.
In this chapter, we will go through some commonly used specifications, and check out what their role is and what you should expect in terms of the impact on your runtime. In the end, you should be able to do the following:

• Know the services that you can expect from your container and the high-level associated overhead
• Evaluate whether a code pattern can impact the performance
• Judge whether your runtime (Java EE) overhead is normal