What happens if I write my aspects in .java files?
AJDT does not support aspects written in .java files. Although
the compiler will compile them correctly, you will find some
loss of functionality in AJDT if you do use .java files for your aspects:
- The Outline and Package Explorer views will not show aspects or their contents.
- The Cross References view will not show any information for an aspect in a .java file, although it will
show information for any classes advised by that aspect.
AspectJ editor

Creating a new aspect
Converting file extensions