# Package javax.lang.model.element

package javax.lang.model.element
Interfaces used to model elements of the Java programming language. The term "element" in this package is used to refer to program elements, the declared entities that make up a program. Elements include classes, interfaces, methods, constructors, and fields. The interfaces in this package do not model the structure of a program inside a method body; for example, there is no representation of a `for` loop or `try`-`finally` block. Concretely, there is no model of any abstract syntax tree (AST) structure of a Java program. However, the interfaces can model some structures only appearing inside method bodies, such as local variables, anonymous classes, and exception parameters. Therefore, these interfaces can be used by an AST API to model the declarations found in the method bodies of Java compilation units (JLS 7.3).

When used in the context of annotation processing, an accurate model of the element being represented must be returned. As this is a language model, the source code provides the fiducial (reference) representation of the construct in question rather than a representation in an executable output like a class file. Executable output may serve as the basis for creating a modeling element. However, the process of translating source code to executable output may not permit recovering some aspects of the source code representation. For example, annotations with source retention cannot be recovered from class files and class files might not be able to provide source position information. Names of parameters may not be recoverable from class files. The modifiers on an element created from a class file may differ in some cases from an element for the same declaration created from a source file including:

- `strictfp` on a class or interface
- `final` on a parameter
- `protected`, `private`, and `static` on classes and interfaces

Some elements which are mandated may not be marked as such when created from class files. Additionally, synthetic constructs in a class file, such as accessor methods used in implementing nested classes and bridge methods used in implementing covariant returns, are translation artifacts strictly outside of this model. However, when operating on class files, it is helpful to be able to operate on such elements, screening them out when appropriate.

During annotation processing, operating on incomplete or erroneous programs is necessary; however, there are fewer guarantees about the nature of the resulting model. If the source code is not syntactically well-formed or has some other irrecoverable error that could not be removed by the generation of new classes or interfaces, a model may or may not be provided as a quality of implementation issue. If a program for a class or interface is syntactically valid but erroneous in some other fashion, any returned model must have no less information than if all the method bodies in the program were replaced by `"throw new RuntimeException();"`. If a program refers to a missing class or interface Xyz, the returned model must contain no less information than if the declaration of class or interface Xyz were assumed to be `"class Xyz {}"`, `"interface Xyz {}"`, `"enum Xyz {}"`, `"@interface Xyz {}"`, or `"record Xyz {}"`. If a program refers to a missing class or interface `Xyz<K1, ... ,Kn>`, the returned model must contain no less information than if the declaration of Xyz were assumed to be `"class Xyz<T1, ... ,Tn> {}"` or `"interface Xyz<T1, ... ,Tn> {}"`

Unless otherwise specified in a particular implementation, the collections returned by methods in this package should be expected to be unmodifiable by the caller and unsafe for concurrent access.

Unless otherwise specified, methods in this package will throw a `NullPointerException` if given a `null` argument.

See Java Language Specification:
  6.1 Declarations
  7.4 Package Declarations
  7.7 Module Declarations
  8.1 Class Declarations
  8.3 Field Declarations
  8.4 Method Declarations
  8.5 Member Class and Interface Declarations
  8.8 Constructor Declarations
  9.1 Interface Declarations
Since:
  1.6
See Also:
  - `Elements`
  - Elements and Types
  - JSR 269: Pluggable Annotation Processing API

- Related Packages
  Package
  Description
  javax.lang.model
  Types and hierarchies of packages comprising a Java language model, a reflective API that models the declarations and types of the Java programming language.
  javax.lang.model.type
  Interfaces used to model Java programming language types.
  javax.lang.model.util
  Utilities to assist in the processing of program elements and types.
- Class
  Description
  AnnotationMirror
  Represents an annotation.
  AnnotationValue
  Represents a value of an annotation interface element.
  AnnotationValueVisitor<R,P>
  A visitor of the values of annotation interface elements, using a variant of the visitor design pattern.
  Element
  Represents a program element such as a module, package, class, or method.
  ElementKind
  The `kind` of an element.
  ElementVisitor<R,P>
  A visitor of program elements, in the style of the visitor design pattern.
  ExecutableElement
  Represents a method, constructor, or initializer (static or instance) of a class or interface, including annotation interface elements.
  Modifier
  Represents a modifier on a program element such as a class, method, or field.
  ModuleElement
  Represents a module program element.
  ModuleElement.Directive
  Represents a directive within the declaration of this module.
  ModuleElement.DirectiveKind
  The `kind` of a directive.
  ModuleElement.DirectiveVisitor<R,P>
  A visitor of module directives, in the style of the visitor design pattern.
  ModuleElement.ExportsDirective
  An exported package of a module.
  ModuleElement.OpensDirective
  An opened package of a module.
  ModuleElement.ProvidesDirective
  An implementation of a service provided by a module.
  ModuleElement.RequiresDirective
  A dependency of a module.
  ModuleElement.UsesDirective
  A reference to a service used by a module.
  Name
  An immutable sequence of characters.
  NestingKind
  The nesting kind of a type element.
  PackageElement
  Represents a package program element.
  Parameterizable
  A mixin interface for an element that has type parameters.
  QualifiedNameable
  A mixin interface for an element that has a qualified name.
  RecordComponentElement
  Represents a record component.
  TypeElement
  Represents a class or interface program element.
  TypeParameterElement
  Represents a formal type parameter of a generic class, interface, method, or constructor element.
  UnknownAnnotationValueException
  Indicates that an unknown kind of annotation value was encountered.
  UnknownDirectiveException
  Indicates that an unknown kind of module directive was encountered.
  UnknownElementException
  Indicates that an unknown kind of element was encountered.
  VariableElement
  Represents a field, `enum` constant, method or constructor parameter, local variable, resource variable, or exception parameter.