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package java.lang.annotation;


The constants of this enumerated type provide a simple classification of the syntactic locations where annotations may appear in a Java program. These constants are used in Target meta-annotations to specify where it is legal to write annotations of a given type. 
The syntactic locations where annotations may appear are split into
declaration contexts , where annotations apply to declarations, and
type contexts , where annotations apply to types used in
declarations and expressions.

The constants ANNOTATION_TYPE, CONSTRUCTOR, FIELD, LOCAL_VARIABLE, METHOD, PACKAGE, MODULE, PARAMETER, TYPE, and TYPE_PARAMETER correspond to the declaration contexts in JLS 9.6.4.1. 
For example, an annotation whose type is meta-annotated with @Target(ElementType.FIELD) may only be written as a modifier for a field declaration. 
The constant TYPE_USE corresponds to the type contexts in JLS 4.11, as well as to two declaration contexts: type declarations (including annotation type declarations) and type parameter declarations. 
For example, an annotation whose type is meta-annotated with @Target(ElementType.TYPE_USE) may be written on the type of a field (or within the type of the field, if it is a nested, parameterized, or array type), and may also appear as a modifier for, say, a class declaration. 
The TYPE_USE constant includes type declarations and type parameter declarations as a convenience for designers of type checkers which give semantics to annotation types. For example, if the annotation type NonNull is meta-annotated with @Target(ElementType.TYPE_USE), then @NonNull class C {...} could be treated by a type checker as indicating that all variables of class C are non-null, while still allowing variables of other classes to be non-null or not non-null based on whether @NonNull appears at the variable's declaration. 
Author: Joshua Bloch
Since:1.5
@jls9.6.4.1 @Target
@jls4.1 The Kinds of Types and Values
/**
 * The constants of this enumerated type provide a simple classification of the
 * syntactic locations where annotations may appear in a Java program. These
 * constants are used in {@link java.lang.annotation.Target Target}
 * meta-annotations to specify where it is legal to write annotations of a
 * given type.
 *
 * <p>The syntactic locations where annotations may appear are split into
 * <em>declaration contexts</em> , where annotations apply to declarations, and
 * <em>type contexts</em> , where annotations apply to types used in
 * declarations and expressions.
 *
 * <p>The constants {@link #ANNOTATION_TYPE}, {@link #CONSTRUCTOR}, {@link
 * #FIELD}, {@link #LOCAL_VARIABLE}, {@link #METHOD}, {@link #PACKAGE}, {@link
 * #MODULE}, {@link #PARAMETER}, {@link #TYPE}, and {@link #TYPE_PARAMETER}
 * correspond to the declaration contexts in JLS 9.6.4.1.
 *
 * <p>For example, an annotation whose type is meta-annotated with
 * {@code @Target(ElementType.FIELD)} may only be written as a modifier for a
 * field declaration.
 *
 * <p>The constant {@link #TYPE_USE} corresponds to the type contexts in JLS
 * 4.11, as well as to two declaration contexts: type declarations (including
 * annotation type declarations) and type parameter declarations.
 *
 * <p>For example, an annotation whose type is meta-annotated with
 * {@code @Target(ElementType.TYPE_USE)} may be written on the type of a field
 * (or within the type of the field, if it is a nested, parameterized, or array
 * type), and may also appear as a modifier for, say, a class declaration.
 *
 * <p>The {@code TYPE_USE} constant includes type declarations and type
 * parameter declarations as a convenience for designers of type checkers which
 * give semantics to annotation types. For example, if the annotation type
 * {@code NonNull} is meta-annotated with
 * {@code @Target(ElementType.TYPE_USE)}, then {@code @NonNull}
 * {@code class C {...}} could be treated by a type checker as indicating that
 * all variables of class {@code C} are non-null, while still allowing
 * variables of other classes to be non-null or not non-null based on whether
 * {@code @NonNull} appears at the variable's declaration.
 *
 * @author  Joshua Bloch
 * @since 1.5
 * @jls 9.6.4.1 @Target
 * @jls 4.1 The Kinds of Types and Values
 */
public enum ElementType {
    
Class, interface (including annotation type), or enum declaration 
/** Class, interface (including annotation type), or enum declaration */
    TYPE,

    
Field declaration (includes enum constants) 
/** Field declaration (includes enum constants) */
    FIELD,

    
Method declaration 
/** Method declaration */
    METHOD,

    
Formal parameter declaration 
/** Formal parameter declaration */
    PARAMETER,

    
Constructor declaration 
/** Constructor declaration */
    CONSTRUCTOR,

    
Local variable declaration 
/** Local variable declaration */
    LOCAL_VARIABLE,

    
Annotation type declaration 
/** Annotation type declaration */
    ANNOTATION_TYPE,

    
Package declaration 
/** Package declaration */
    PACKAGE,

    
Type parameter declaration

Since:1.8
/**
     * Type parameter declaration
     *
     * @since 1.8
     */
    TYPE_PARAMETER,

    
Use of a type

Since:1.8
/**
     * Use of a type
     *
     * @since 1.8
     */
    TYPE_USE,

    
Module declaration.

Since:9
/**
     * Module declaration.
     *
     * @since 9
     */
    MODULE
}