- A note by way of explanation or comment added to a text or diagram.
- The action of annotating a text or diagram.
Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate.
Annotations have a number of uses, among them:
Information for the compiler — Annotations can be used by the compiler to detect errors or suppress warnings.
Compiler-time and deployment-time processing — Software tools can process annotation information to generate code, XML files, and so forth.
Runtime processing — Some annotations are available to be examined at runtime.
Annotations can be applied to a program’s declarations of classes, fields, methods, and other program elements.