5.1 Java and J2EE
We assume that the primary audience for this book consists of system architects and administrators responsible for designing, deploying, and managing WAS on System p and AIX. In the following sections we provide background on Java and J2EE for that audience.
Having standards like Java allowed client application vendors to write code without too much concern as to the platform it would be run on. The J2EE standard allows server-side code to be produced that can target a myriad of high-end enterprise platforms with testing only required (in theory) to certify for that platform. This reduces costs for the enterprise software vendor and allows customers to choose the platform that suits their needs without being driven by application software requirements.
So, how does this fact relate to WAS? WAS is the premier IBM implementation of the J2EE standard specification. J2EE is the standard and WAS is an implementation of that standard that provides all the services and interfaces that meet that specification.
AIX and WAS system administrators and application developers should understand that there are a number of things going on in the Java runtime environment inside the WAS process container, as well as a number of things going on outside the WAS process container that are interdependent. For instance, failover of functionality can occur both inside the JVM to another JVM, or outside the JVM to start another JVM, or something the JVM is communicating with (that is, a DBMS instance, MQ queue manager, and so on).