Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Java Metadata Facility

  • David J. Buttler
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_910

Synonyms

Java annotations; Java metadata facility; JSR 175

Definition

The Java Metadata Facility is introduced by Java Specification Request (JSR) 175 [1], and incorporated into the Java language specification [2] in version 1.5 of the language. The specification allows annotations on Java program elements: classes, interfaces, methods, and fields. Annotations give programmers a uniform way to add metadata to program elements that can be used by code checkers, code generators, or other compile-time or runtime components.

Annotations are defined by annotation types. These are defined the same way as interfaces, but with the symbol “@”; preceding the “interface” keyword. There are additional restrictions on defining annotation types:
  1. 1.

    They cannot be generic.

     
  2. 2.

    They cannot extend other annotation types or interfaces.

     
  3. 3.

    Methods cannot have any parameters.

     
  4. 4.

    Methods cannot have type parameters.

     
  5. 5.

    Methods cannot throw exceptions.

     
  6. 6.

    The return type of methods of an annotation...

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Recommended Reading

  1. 1.
    Coward D. JSR 175: a metadata facility for the Java™ Programming Language, 2004. http://jcp.org/en/jsr/detail?id=175
  2. 2.
    Gosling J, Joy B, Steele G, Bracha G. The Java™ language specification. Englewood Cliffs: Prentice Hall; 2005.zbMATHGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Lawrence Livermore National LaboratoryLivermoreUSA

Section editors and affiliations

  • Manfred Jeusfeld
    • 1
  1. 1.IITUniversity of SkövdeSkövdeSweden