The Art of Metaprogramming in Java

The Art of Metaprogramming in Java

Metaprograming is the dirty little secret behind the success of many Java frameworks such as Spring and Struts2, and constitutes the backbone of many of the most fundamental APIs across the JEE technology stack. This session aims introduce the topic and highlight, with code examples, the different mechanisms and techniques to take advantage of this underused feature of the Java Programming Language.

This session will adopt a learn-by-example approach that combines the philosophy and theory behind metaprogramming with concrete code examples. The audience will be walked real-life scenarios to highlight the benefits of this technique such as minimizing the number of lines of code, reduced development time, and greater flexibility, etc… Design patterns, and best practices will be picked up along the way.

No previous knowledge or exposure to the topic is required, but an intermediate understanding of Java SE is expected.

Outline:

• What is Metaprogramming?
• Metadata Formats?
• Benefit?
• Example: (Spring, etc…)

• Java Annotations – JSR 175
• Annotation Processing

• Compile time:
1. APT (Annotation Processing Tool) and Pluggable Annotation Processing API (JSR 269)

• Runtime:
1. Java Reflection API
2. Libraries: Reflections, FEST-Reflect, etc…

• ASM, CGLib, and Javassist
• Project Averroes

• A step-by-step code example
1. The metadata
2. Metadata processing
3. Constructing a metamodel
4. Making sense of the metamodel