Annotations are tags that you insert into your source code so that some tool can process them. The tools can operate on the source level, or they can process class files into which the compiler has placed annotations.
Annotations do not change the way in which your programs are compiled. The Java compiler generates the same virtual machine instructions with or without the annotations.
To benefit from annotations, you need to select a processing tool. You need to use annotations that your processing tool understands, then apply the processing tool to your code.
There is a wide range of uses for annotations, and that generality can be confusing at first. Here are some uses for annotations:
• Automatic generation of auxiliary ...