Module java.base
Package java.lang.annotation

Interface Annotation

All Known Implementing Classes:
BeanProperty, BooleanFlag, Category, ConstructorParameters, ConstructorProperties, ContentType, DataAmount, Deprecated, Description, DescriptorKey, Documented, Enabled, Experimental, Frequency, FunctionalInterface, Generated, Inherited, JavaBean, Label, MemoryAddress, MetadataDefinition, MXBean, Name, Native, Override, Percentage, Period, Registered, Relational, Repeatable, Retention, SafeVarargs, Serial, SettingDefinition, StackTrace, SupportedAnnotationTypes, SupportedOptions, SupportedSourceVersion, SuppressWarnings, SwingContainer, Target, Threshold, Timespan, Timestamp, Transient, TransitionFrom, TransitionTo, Unsigned
public interface Annotation
The common interface extended by all annotation types. Note that an interface that manually extends this one does not define an annotation type. Also note that this interface does not itself define an annotation type. More information about annotation types can be found in section 9.6 of The Java™ Language Specification. The AnnotatedElement interface discusses compatibility concerns when evolving an annotation type from being non-repeatable to being repeatable.
Since:
1.5

  • Method Summary

    Modifier and Type Method Description
    Class<? extends Annotation> annotationType()
    Returns the annotation type of this annotation.
    boolean equals​(Object obj)
    Returns true if the specified object represents an annotation that is logically equivalent to this one.
    int hashCode()
    Returns the hash code of this annotation, as defined below:
    String toString()
    Returns a string representation of this annotation.

  • Method Details

    • equals

      boolean equals​(Object obj)
      Returns true if the specified object represents an annotation that is logically equivalent to this one. In other words, returns true if the specified object is an instance of the same annotation type as this instance, all of whose members are equal to the corresponding member of this annotation, as defined below:
      • Two corresponding primitive typed members whose values are x and y are considered equal if x == y, unless their type is float or double.
      • Two corresponding float members whose values are x and y are considered equal if Float.valueOf(x).equals(Float.valueOf(y)). (Unlike the == operator, NaN is considered equal to itself, and 0.0f unequal to -0.0f.)
      • Two corresponding double members whose values are x and y are considered equal if Double.valueOf(x).equals(Double.valueOf(y)). (Unlike the == operator, NaN is considered equal to itself, and 0.0 unequal to -0.0.)
      • Two corresponding String, Class, enum, or annotation typed members whose values are x and y are considered equal if x.equals(y). (Note that this definition is recursive for annotation typed members.)
      • Two corresponding array typed members x and y are considered equal if Arrays.equals(x, y), for the appropriate overloading of Arrays.equals(long[], long[]).
      Overrides:
      equals in class Object
      Parameters:
      obj - the reference object with which to compare.
      Returns:
      true if the specified object represents an annotation that is logically equivalent to this one, otherwise false
      See Also:
      Object.hashCode(), HashMap

    • hashCode

      int hashCode()
      Returns the hash code of this annotation, as defined below:

      The hash code of an annotation is the sum of the hash codes of its members (including those with default values), as defined below: The hash code of an annotation member is (127 times the hash code of the member-name as computed by String.hashCode()) XOR the hash code of the member-value, as defined below:

      The hash code of a member-value depends on its type:

      • The hash code of a primitive value v is equal to WrapperType.valueOf(v).hashCode(), where WrapperType is the wrapper type corresponding to the primitive type of v (Byte, Character, Double, Float, Integer, Long, Short, or Boolean).
      • The hash code of a string, enum, class, or annotation member-value I v is computed as by calling v.hashCode(). (In the case of annotation member values, this is a recursive definition.)
      • The hash code of an array member-value is computed by calling the appropriate overloading of Arrays.hashCode on the value. (There is one overloading for each primitive type, and one for object reference types.)

      Overrides:
      hashCode in class Object
      Returns:
      the hash code of this annotation
      See Also:
      Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

    • toString

      String toString()
      Returns a string representation of this annotation. The details of the representation are implementation-dependent, but the following may be regarded as typical: 
         @com.acme.util.Name(first=Alfred, middle=E., last=Neuman)
      Overrides:
      toString in class Object
      Returns:
      a string representation of this annotation

    • annotationType

      Class<? extends Annotation> annotationType()
      Returns the annotation type of this annotation.
      Returns:
      the annotation type of this annotation