Annotation

Annotation is one more powerful feature of Java, an object-oriented programming language included in JDK 1.5.

Annotation

Annotation is one more powerful feature of Java, an object-oriented programming language included in JDK 1.5.

Annotation

Annotation

     

Annotation is one more powerful feature of Java, an object-oriented programming language included in JDK 1.5. Annotations were introduced in September 2004  and added to the Java language through specification. It is a way of adding the informative data to Java source code or to the Java elements like Classes, Interfaces or Enums that can also be available for the programmer at run-time that is not actually part of the program.

After adding annotation by Sun Microsystem, it is very easy to make the development of program as well as efficient in jdk 5. Annotations behave like the meta-data where the literal meaning of meta-data is data about data. Java also signifies this meaning. Annotations can also apply on variables, parameter, field type declarations, methods and constructors. Annotation is also used to create the documentation to perform rudimentary compile time checking and even for tracking down the dependencies in code. XDoclet contains all these features and is widely used. Annotation is the way to associate the program elements with the meta-tags so that the compiler can extract program behavior to support the annotated elements to generate interdependent code when necessary.

Fundamentals of annotations

An annotation type definition appends an "at" @ sign at the start of the interface keyword with the annotation name. On the other hand, an annotation includes the "at" @ sign followed by the annotation type. You can also add the data within the parenthesis after the annotation name.

First of all before going through the annotations we should consider two things. The first one is the "annotation" itself and second one is the "annotations types". An annotation is the meta tag, used to give some life to the code you are using. While annotation type is used to define annotations so that you can use them while creating your own custom annotations.

For detailed information about annotation just visit on  Annotation in brief: