May 2020
Beginner
267 pages
7h 37m
English
Content preview from 97 Things Every Java Programmer Should Know
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Chapter 25. Follow the Boring Standards
Adam Bien
At the beginning of the Java age, there were dozens of incompatible application servers on the market, and the server vendors followed completely different paradigms. Some servers were even partially implemented in native languages like C++. Understanding multiple servers was hard, and porting an application from one server to another was nearly impossible.
APIs like JDBC (introduced with JDK 1.1), JNDI (introduced with JDK 1.3), JMS, JPA, or Servlets abstracted, simplified, and unified already established products. EJBs and CDI made the deployment and programming models vendor agnostic. J2EE, later Java EE and now Jakarta EE, and MicroProfile defined a minimal set of APIs an application server had to implement. With the advent of J2EE, a developer only had to know a set of J2EE APIs to develop and deploy an application.
Although the servers evolved, the J2EE and Java EE APIs remained compatible. You never had to migrate your application to run on a newer release of the application server. Even upgrading to a higher Java EE version was painless. You only had to re-test the application without even recompiling it. Only if you wanted to take advantage of newer APIs did you have to refactor the application. With the introduction of J2EE, developers could master multiple application servers without delving too deep into their specifics. ...