Defining your own Annotations

You can use the @Interface annotation to create your own annotation definition.

To define your own annotations:

Use the @Interface annotation to define your own annotation definition:

• Annotation definitions resemble interface definitions

• Annotation method declarations have neither parameters nor throws clauses, and return one of the following elements:

  • primitives

  • String

  • Class

  • enum

  • array of the above types

• Methods may have default values

public @interface CreatedBy{
     String name();
     String date();
     boolean contractor() default false;
}          

@CreatedBy(name = "Mary Smith",date="02/02/2008");
public class MyClass{....}         

Meta-annotations: Meta-annotations (annotations of annotations) provide additional information on how an annotation should be used:

• @Target

  • Restricts the use of an annotation

  • Single argument must be from Enum ElementType

    • {TYPE, FIELD,METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE, ANNOTATION_TYPE}

• @Retention

  • Indicates where the annotation information will be retained

  • Single argument must be from Enum RetentionPolicy

    • {SOURCE, CLASS, RUNTIME}

• @Documented

  • Marker for annotations that should be included in Javadoc

• @Inherited

  • marker for Type annotations that are to be inherited by subtypes

Other built-in annotations:

• @Overrides

  • Applied to a method

  • Indicates that the compiler should generate an error if the method does not actually override a superclass method.

• @Deprecated

  • Applied to a method

  • Indicates that the compiler should generate a warning when the method is used externally

• @SuppressWarnings

  • Applies to a type or a method

  • Indicates that the compiler should supress warnings for that element and all subelements

    @Deprecated
    public void oldMethod() {...}
    
    @ SupressWarnings
    public void yesIknowIuseDeprecatedMethods() {...}

 

Related concepts

Creating and configuring Java EE modules using annotations

Scope and placement of annotations

Using the Annotations view

 

Related tasks

Adding annotations

Editing annotations

Removing annotations

Overridden annotations

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