Defaults in Java EE 7 (Tech Tip #37)
Java EE 7 platform added a few new specifications to the platform:
- Java API for WebSocket 1.0
- Batch Applications for Java 1.0
- Java API for JSON Processing 1.0
- Concurrency Utilities for Java EE 1.0
This is highlighted in the pancake diagram shown below:
Several of the existing specifications were updated to fill the gaps and provide a more cohesive platform. Some small, but rather significant additions, were made to the platform to provide defaults for different features. These defaults would lower the bar for application developers to build Java EE applications.
Lets take a look at them.
- Default CDI: Java EE 6 required "beans.xml" in an archive to enable CDI. This was mostly a marker file. So you could bundle a completely empty "beans.xml" in the archive and that would enable injection. Of course, you could specify a lot of other elements in this file such as interceptors, decorators, alternative but the basic dependency injection was enabled by just the mere inclusion of this file.This was one of the biggest source of confusion of why beans were not getting injected in a Java EE 7 archive, and was asked on several forums and other channels.Java EE 7 made that "beans.xml" optional and provided a default behavior. Now if this file is not bundled, all CDI-scoped beans are available for injection. So any bean with an explicitly specified scope is available for injection. Scopes defined by the CDI specification are listed at
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