AccessFlag (Java SE 21 & JDK 21)
Description: declaration: module: java.base, package: java.lang.reflect, enum: AccessFlag
Keywords: java.lang.reflect.AccessFlag class

Module java.base
Package java.lang.reflect

# Enum Class AccessFlag

java.lang.Object
java.lang.Enum<AccessFlag>
java.lang.reflect.AccessFlag

All Implemented Interfaces:
  `Serializable`, `Comparable<AccessFlag>`, `Constable`

public enum AccessFlag extends Enum<AccessFlag>
Represents a JVM access or module-related flag on a runtime member, such as a class, field, or method.

JVM access and module-related flags are related to, but distinct from Java language modifiers. Some modifiers and access flags have a one-to-one correspondence, such as `public`. In other cases, some language-level modifiers do not have an access flag, such as `sealed` (JVMS 4.7.31) and some access flags have no corresponding modifier, such as synthetic.

The values for the constants representing the access and module flags are taken from sections of The Java Virtual Machine Specification including 4.1 (class access and property modifiers), 4.5 (field access and property flags), 4.6 (method access and property flags), 4.7.6 (nested class access and property flags), 4.7.24 (method parameters), and 4.7.25 (module flags and requires, exports, and opens flags).

The mask values for the different access flags are not distinct. Flags are defined for different kinds of JVM structures and the same bit position has different meanings in different contexts. For example, `0x0000_0040` indicates a `volatile` field but a bridge method; `0x0000_0080` indicates a `transient` field but a variable arity (varargs) method.

API Note:
  The JVM class file format has a new version defined for each new feature release. A new class file version may define new access flags or retire old ones. `AccessFlag` is intended to model the set of access flags across class file format versions. The range of versions an access flag is recognized is not explicitly indicated in this API. See the current The Java Virtual Machine Specification for details. Unless otherwise indicated, access flags can be assumed to be recognized in the current version.
Implementation Requirements:
  The access flag constants are ordered by non-decreasing mask value; that is the mask value of a constant is greater than or equal to the mask value of an immediate neighbor to its (syntactic) left. If new constants are added, this property will be maintained. That implies new constants will not necessarily be added at the end of the existing list.
Since:
  20
See Also:
  - `Modifier`
  - `ModuleDescriptor.Modifier`
  - `ModuleDescriptor.Requires.Modifier`
  - `ModuleDescriptor.Exports.Modifier`
  - `ModuleDescriptor.Opens.Modifier`
  - `Modifier`

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static enum`
  `AccessFlag.Location`
  A location within a class file where flags can be applied.

  ## Nested classes/interfaces declared in class java.lang.Enum

  `Enum.EnumDesc<E extends Enum<E>>`

- ## Enum Constant Summary

  Enum Constants
  Enum Constant
  Description
  `ABSTRACT`
  The access flag `ACC_ABSTRACT`, corresponding to the source modifier `abstract`, with a mask value of `0x0400`.
  `ANNOTATION`
  The access flag `ACC_ANNOTATION` with a mask value of `0x2000`.
  `BRIDGE`
  The access flag `ACC_BRIDGE` with a mask value of `0x0040`
  `ENUM`
  The access flag `ACC_ENUM` with a mask value of `0x4000`.
  `FINAL`
  The access flag `ACC_FINAL`, corresponding to the source modifier `final`, with a mask value of `0x0010`.
  `INTERFACE`
  The access flag `ACC_INTERFACE` with a mask value of `0x0200`.
  `MANDATED`
  The access flag `ACC_MANDATED` with a mask value of `0x8000`.
  `MODULE`
  The access flag `ACC_MODULE` with a mask value of `0x8000`.
  `NATIVE`
  The access flag `ACC_NATIVE`, corresponding to the source modifier `native`, with a mask value of `0x0100`.
  `OPEN`
  The module flag `ACC_OPEN` with a mask value of `0x0020`.
  `PRIVATE`
  The access flag `ACC_PRIVATE`, corresponding to the source modifier `private`, with a mask value of `0x0002`.
  `PROTECTED`
  The access flag `ACC_PROTECTED`, corresponding to the source modifier `protected`, with a mask value of `0x0004`.
  `PUBLIC`
  The access flag `ACC_PUBLIC`, corresponding to the source modifier `public`, with a mask value of `0x0001`.
  `STATIC`
  The access flag `ACC_STATIC`, corresponding to the source modifier `static`, with a mask value of `0x0008`.
  `STATIC_PHASE`
  The module requires flag `ACC_STATIC_PHASE` with a mask value of `0x0040`.
  `STRICT`
  The access flag `ACC_STRICT`, corresponding to the source modifier `strictfp`, with a mask value of `0x0800`.
  `SUPER`
  The access flag `ACC_SUPER` with a mask value of `0x0020`.
  `SYNCHRONIZED`
  The access flag `ACC_SYNCHRONIZED`, corresponding to the source modifier `synchronized`, with a mask value of `0x0020`.
  `SYNTHETIC`
  The access flag `ACC_SYNTHETIC` with a mask value of `0x1000`.
  `TRANSIENT`
  The access flag `ACC_TRANSIENT`, corresponding to the source modifier `transient`, with a mask value of `0x0080`.
  `TRANSITIVE`
  The module requires flag `ACC_TRANSITIVE` with a mask value of `0x0020`.
  `VARARGS`
  The access flag `ACC_VARARGS` with a mask value of `0x0080`.
  `VOLATILE`
  The access flag `ACC_VOLATILE`, corresponding to the source modifier `volatile`, with a mask value of `0x0040`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Set<AccessFlag.Location>`
  `locations()`
  Returns kinds of constructs the flag can be applied to in the latest class file format version.
  `Set<AccessFlag.Location>`
  `locations(ClassFileFormatVersion cffv)`
  Returns kinds of constructs the flag can be applied to in the given class file format version.
  `int`
  `mask()`
  Returns the corresponding integer mask for the access flag.
  `static Set<AccessFlag>`
  `maskToAccessFlags(int mask, AccessFlag.Location location)`
  Returns an unmodifiable set of access flags for the given mask value appropriate for the location in question.
  `boolean`
  `sourceModifier()`
  Returns whether or not the flag has a directly corresponding modifier in the Java programming language.
  `static AccessFlag`
  `valueOf(String name)`
  Returns the enum constant of this class with the specified name.
  `static AccessFlag[]`
  `values()`
  Returns an array containing the constants of this enum class, in the order they are declared.

  ### Methods declared in class java.lang.Enum

  `clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf`

  ### Methods declared in class java.lang.Object

  `getClass, notify, notifyAll, wait, wait, wait`

- ## Enum Constant Details

  - ### PUBLIC

    public static final AccessFlag PUBLIC
    The access flag `ACC_PUBLIC`, corresponding to the source modifier `public`, with a mask value of `0x0001`.

  - ### PRIVATE

    public static final AccessFlag PRIVATE
    The access flag `ACC_PRIVATE`, corresponding to the source modifier `private`, with a mask value of `0x0002`.

  - ### PROTECTED

    public static final AccessFlag PROTECTED
    The access flag `ACC_PROTECTED`, corresponding to the source modifier `protected`, with a mask value of `0x0004`.

  - ### STATIC

    public static final AccessFlag STATIC
    The access flag `ACC_STATIC`, corresponding to the source modifier `static`, with a mask value of `0x0008`.

  - ### FINAL

    public static final AccessFlag FINAL
    The access flag `ACC_FINAL`, corresponding to the source modifier `final`, with a mask value of `0x0010`.

  - ### SUPER

    public static final AccessFlag SUPER
    The access flag `ACC_SUPER` with a mask value of `0x0020`.
    API Note:
      In Java SE 8 and above, the JVM treats the `ACC_SUPER` flag as set in every class file (JVMS 4.1).

  - ### OPEN

    public static final AccessFlag OPEN
    The module flag `ACC_OPEN` with a mask value of `0x0020`.
    See Also:
      - `ModuleDescriptor.isOpen()`

  - ### TRANSITIVE

    public static final AccessFlag TRANSITIVE
    The module requires flag `ACC_TRANSITIVE` with a mask value of `0x0020`.
    See Also:
      - `ModuleDescriptor.Requires.Modifier.TRANSITIVE`

  - ### SYNCHRONIZED

    public static final AccessFlag SYNCHRONIZED
    The access flag `ACC_SYNCHRONIZED`, corresponding to the source modifier `synchronized`, with a mask value of `0x0020`.

  - ### STATIC_PHASE

    public static final AccessFlag STATIC_PHASE
    The module requires flag `ACC_STATIC_PHASE` with a mask value of `0x0040`.
    See Also:
      - `ModuleDescriptor.Requires.Modifier.STATIC`

  - ### VOLATILE

    public static final AccessFlag VOLATILE
    The access flag `ACC_VOLATILE`, corresponding to the source modifier `volatile`, with a mask value of `0x0040`.

  - ### BRIDGE

    public static final AccessFlag BRIDGE
    The access flag `ACC_BRIDGE` with a mask value of `0x0040`
    See Also:
      - `Method.isBridge()`

  - ### TRANSIENT

    public static final AccessFlag TRANSIENT
    The access flag `ACC_TRANSIENT`, corresponding to the source modifier `transient`, with a mask value of `0x0080`.

  - ### VARARGS

    public static final AccessFlag VARARGS
    The access flag `ACC_VARARGS` with a mask value of `0x0080`.
    See Also:
      - `Executable.isVarArgs()`

  - ### NATIVE

    public static final AccessFlag NATIVE
    The access flag `ACC_NATIVE`, corresponding to the source modifier `native`, with a mask value of `0x0100`.

  - ### INTERFACE

    public static final AccessFlag INTERFACE
    The access flag `ACC_INTERFACE` with a mask value of `0x0200`.
    See Also:
      - `Class.isInterface()`

  - ### ABSTRACT

    public static final AccessFlag ABSTRACT
    The access flag `ACC_ABSTRACT`, corresponding to the source modifier `abstract`, with a mask value of `0x0400`.

  - ### STRICT

    public static final AccessFlag STRICT
    The access flag `ACC_STRICT`, corresponding to the source modifier `strictfp`, with a mask value of `0x0800`.
    API Note:
      The `ACC_STRICT` access flag is defined for class file major versions 46 through 60, inclusive (JVMS 4.6), corresponding to Java SE 1.2 through 16.

  - ### SYNTHETIC

    public static final AccessFlag SYNTHETIC
    The access flag `ACC_SYNTHETIC` with a mask value of `0x1000`.
    See Also:
      - `Class.isSynthetic()`
      - `Executable.isSynthetic()`
      - `ModuleDescriptor.Modifier.SYNTHETIC`

  - ### ANNOTATION

    public static final AccessFlag ANNOTATION
    The access flag `ACC_ANNOTATION` with a mask value of `0x2000`.
    See Also:
      - `Class.isAnnotation()`

  - ### ENUM

    public static final AccessFlag ENUM
    The access flag `ACC_ENUM` with a mask value of `0x4000`.
    See Also:
      - `Class.isEnum()`

  - ### MANDATED

    public static final AccessFlag MANDATED
    The access flag `ACC_MANDATED` with a mask value of `0x8000`.

  - ### MODULE

    public static final AccessFlag MODULE
    The access flag `ACC_MODULE` with a mask value of `0x8000`.

- ## Method Details

  - ### values

    public static AccessFlag[] values()
    Returns an array containing the constants of this enum class, in the order they are declared.
    Returns:
      an array containing the constants of this enum class, in the order they are declared

  - ### valueOf

    public static AccessFlag valueOf(String name)
    Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
    Parameters:
      `name` - the name of the enum constant to be returned.
    Returns:
      the enum constant with the specified name
    Throws:
      `IllegalArgumentException` - if this enum class has no constant with the specified name
      `NullPointerException` - if the argument is null

  - ### mask

    public int mask()
    Returns the corresponding integer mask for the access flag.
    Returns:
      the corresponding integer mask for the access flag

  - ### sourceModifier

    public boolean sourceModifier()
    Returns whether or not the flag has a directly corresponding modifier in the Java programming language.
    Returns:
      whether or not the flag has a directly corresponding modifier in the Java programming language

  - ### locations

    public Set<AccessFlag.Location> locations()
    Returns kinds of constructs the flag can be applied to in the latest class file format version.
    Returns:
      kinds of constructs the flag can be applied to in the latest class file format version

  - ### locations

    public Set<AccessFlag.Location> locations(ClassFileFormatVersion cffv)
    Returns kinds of constructs the flag can be applied to in the given class file format version.
    Parameters:
      `cffv` - the class file format version to use
    Returns:
      kinds of constructs the flag can be applied to in the given class file format version
    Throws:
      `NullPointerException` - if the parameter is `null`

  - ### maskToAccessFlags

    public static Set<AccessFlag> maskToAccessFlags(int mask, AccessFlag.Location location)
    Returns an unmodifiable set of access flags for the given mask value appropriate for the location in question.
    Parameters:
      `mask` - bit mask of access flags
      `location` - context to interpret mask value
    Returns:
      an unmodifiable set of access flags for the given mask value appropriate for the location in question
    Throws:
      `IllegalArgumentException` - if the mask contains bit positions not support for the location in question