T - the type of the class modeled by this Class object. For example, the type of String.class is Class<String>. Use Class<?> if the class being modeled is unknown.
Serializable, Constable, TypeDescriptor, TypeDescriptor.OfField<Class<?>>, AnnotatedElement, GenericDeclaration, Type
Instances of the class
Class
represent classes and interfaces in a running Java application. An enum class and a record class are kinds of class; an annotation interface is a kind of interface. Every array also belongs to a class that is reflected as a
Class
object that is shared by all arrays with the same element type and number of dimensions. The primitive Java types (
boolean
,
byte
,
char
,
short
,
int
,
long
,
float
, and
double
), and the keyword
void
are also represented as
Class
objects.
Class has no public constructor. Instead a Class object is constructed automatically by the Java Virtual Machine when a class is derived from the bytes of a class file through the invocation of one of the following methods:
ClassLoader::defineClassjava.lang.invoke.MethodHandles.Lookup::defineClassjava.lang.invoke.MethodHandles.Lookup::defineHiddenClassThe methods of class Class expose many characteristics of a class or interface. Most characteristics are derived from the class file that the class loader passed to the Java Virtual Machine or from the class file passed to Lookup::defineClass or Lookup::defineHiddenClass. A few characteristics are determined by the class loading environment at run time, such as the module returned by getModule().
The following example uses a Class object to print the class name of an object:
void printClassName(Object obj) {
System.out.println("The class of " + obj +
" is " + obj.getClass().getName());
}
It is also possible to get the
Class
object for a named class or interface (or for
void
) using a
class literal. For example:
System.out.println("The name of class Foo is: "+Foo.class.getName());
Some methods of class Class expose whether the declaration of a class or interface in Java source code was enclosed within another declaration. Other methods describe how a class or interface is situated in a nest. A nest is a set of classes and interfaces, in the same run-time package, that allow mutual access to their private members. The classes and interfaces are known as nestmates. One nestmate acts as the nest host, and enumerates the other nestmates which belong to the nest; each of them in turn records it as the nest host. The classes and interfaces which belong to a nest, including its host, are determined when class files are generated, for example, a Java compiler will typically record a top-level class as the host of a nest where the other members are the classes and interfaces whose declarations are enclosed within the top-level class declaration.
A class or interface created by the invocation of Lookup::defineHiddenClass is a hidden class or interface. All kinds of class, including enum classes and record classes, may be hidden classes; all kinds of interface, including annotation interfaces, may be hidden interfaces. The name of a hidden class or interface is not a binary name, which means the following:
Class::describeConstable, ClassDesc::of, or ClassDesc::ofDescriptor.Class::forName or ClassLoader::loadClass.A hidden class or interface is never an array class, but may be the element type of an array. In all other respects, the fact that a class or interface is hidden has no bearing on the characteristics exposed by the methods of class
Class
.
Returns an unmodifiable set of the
access flagsfor this class, possibly empty.
Returns a
Class
for an array type whose component type is described by this
Class.
Casts this Class object to represent a subclass of the class represented by the specified class object.
Casts an object to the class or interface represented by this Class object.
Returns the component type of this Class, if it describes an array type, or null otherwise.
Returns a nominal descriptor for this instance, if one can be constructed, or an empty
Optional
if one cannot be.
Returns the descriptor string of the entity (class, interface, array class, primitive type, or void) represented by this Class object.
boolean
Returns the assertion status that would be assigned to this class if it were to be initialized at the time this method is invoked.
Returns the
Class
with the given
binary namein the given module.
Returns the Class object associated with the class or interface with the given string name.
Returns the Class object associated with the class or interface with the given string name, using the given class loader.
Returns an array of AnnotatedType objects that represent the use of types to specify superinterfaces of the entity represented by this Class object.
Returns an AnnotatedType object that represents the use of a type to specify the superclass of the entity represented by this Class object.
Returns this element's annotation for the specified type if such an annotation is present, else null.
Returns annotations that are present on this element.
Returns annotations that are associated with this element.
Returns the canonical name of the underlying class as defined by The Java Language Specification.
Returns an array containing Class objects representing all the public classes and interfaces that are members of the class represented by this Class object.
Returns the class loader for the class.
Returns the Class representing the component type of an array.
Returns a Constructor object that reflects the specified public constructor of the class represented by this Class object.
Returns an array containing Constructor objects reflecting all the public constructors of the class represented by this Class object.
Returns this element's annotation for the specified type if such an annotation is directly present, else null.
Returns annotations that are directly present on this element.
Returns this element's annotation(s) for the specified type if such annotations are either directly present or indirectly present.
Returns an array of Class objects reflecting all the classes and interfaces declared as members of the class represented by this Class object.
Returns a Constructor object that reflects the specified constructor of the class represented by this Class object.
Returns an array of Constructor objects reflecting all the constructors implicitly or explicitly declared by the class represented by this Class object.
Returns a Field object that reflects the specified declared field of the class or interface represented by this Class object.
Returns an array of Field objects reflecting all the fields declared by the class or interface represented by this Class object.
Returns a Method object that reflects the specified declared method of the class or interface represented by this Class object.
Returns an array containing Method objects reflecting all the declared methods of the class or interface represented by this Class object, including public, protected, default (package) access, and private methods, but excluding inherited methods.
If the class or interface represented by this Class object is a member of another class, returns the Class object representing the class in which it was declared.
Returns the immediately enclosing class of the underlying class.
If this
Class
object represents a local or anonymous class within a constructor, returns a
Constructor
object representing the immediately enclosing constructor of the underlying class.
If this
Class
object represents a local or anonymous class within a method, returns a
Method
object representing the immediately enclosing method of the underlying class.
Returns the elements of this enum class or null if this Class object does not represent an enum class.
Returns a Field object that reflects the specified public member field of the class or interface represented by this Class object.
Returns an array containing Field objects reflecting all the accessible public fields of the class or interface represented by this Class object.
Returns the Types representing the interfaces directly implemented by the class or interface represented by this Class object.
Returns the Type representing the direct superclass of the entity (class, interface, primitive type or void) represented by this Class object.
Returns the interfaces directly implemented by the class or interface represented by this Class object.
Returns a Method object that reflects the specified public member method of the class or interface represented by this Class object.
Returns an array containing Method objects reflecting all the public methods of the class or interface represented by this Class object, including those declared by the class or interface and those inherited from superclasses and superinterfaces.
int
Returns the Java language modifiers for this class or interface, encoded in an integer.
Returns the module that this class or interface is a member of.
Returns the name of the entity (class, interface, array class, primitive type, or void) represented by this Class object.
Returns the nest host of the
nestto which the class or interface represented by this
Class
object belongs.
Returns an array containing Class objects representing all the classes and interfaces that are members of the nest to which the class or interface represented by this Class object belongs.
Gets the package of this class.
Returns the fully qualified package name.
Returns an array containing Class objects representing the direct subinterfaces or subclasses permitted to extend or implement this class or interface if it is sealed.
Returns the ProtectionDomain of this class.
Returns an array of RecordComponent objects representing all the record components of this record class, or null if this class is not a record class.
Finds a resource with a given name.
Finds a resource with a given name.
Gets the signers of this class.
Returns the simple name of the underlying class as given in the source code.
Returns the Class representing the direct superclass of the entity (class, interface, primitive type or void) represented by this Class.
Return an informative string for the name of this class or interface.
Returns an array of TypeVariable objects that represent the type variables declared by the generic declaration represented by this GenericDeclaration object, in declaration order.
boolean
Returns true if this Class object represents an annotation interface.
boolean
Returns true if an annotation for the specified type is present on this element, else false.
boolean
Returns true if and only if the underlying class is an anonymous class.
boolean
Determines if this Class object represents an array class.
boolean
Determines if the class or interface represented by this Class object is either the same as, or is a superclass or superinterface of, the class or interface represented by the specified Class parameter.
boolean
Returns true if and only if this class was declared as an enum in the source code.
boolean
Returns true if and only if the underlying class is a hidden class.
boolean
Determines if the specified Object is assignment-compatible with the object represented by this Class.
boolean
Determines if this Class object represents an interface type.
boolean
Returns true if and only if the underlying class is a local class.
boolean
Returns true if and only if the underlying class is a member class.
boolean
Determines if the given Class is a nestmate of the class or interface represented by this Class object.
boolean
Determines if the specified Class object represents a primitive type.
boolean
Returns true if and only if this class is a record class.
boolean
Returns true if and only if this Class object represents a sealed class or interface.
boolean
Returns true if and only if this class has the synthetic modifier bit set.
Returns a string describing this Class, including information about modifiers and type parameters.
Converts the object to a string.
Converts the object to a string. The string representation is the string "class" or "interface", followed by a space, and then by the name of the class in the format returned by getName. If this Class object represents a primitive type, this method returns the name of the primitive type. If this Class object represents void this method returns "void". If this Class object represents an array type, this method returns "class " followed by getName.
()
Returns a string describing this
Class
, including information about modifiers and type parameters. The string is formatted as a list of type modifiers, if any, followed by the kind of type (empty string for primitive types and
class
,
enum
,
interface
,
@interface
, or
record
as appropriate), followed by the type's name, followed by an angle-bracketed comma-separated list of the type's type parameters, if any, including informative bounds on the type parameters, if any. A space is used to separate modifiers from one another and to separate any modifiers from the kind of type. The modifiers occur in canonical order. If there are no type parameters, the type parameter list is elided. For an array type, the string starts with the type name, followed by an angle-bracketed comma-separated list of the type's type parameters, if any, followed by a sequence of
[]
characters, one set of brackets per dimension of the array.
Note that since information about the runtime representation of a type is being generated, modifiers not present on the originating source code or illegal on the originating source code may be present.
Class, including information about modifiers and type parameters
Returns the
Class
object associated with the class or interface with the given string name. Invoking this method is equivalent to:
Class.forName(className, true, currentLoader)
where
currentLoader
denotes the defining class loader of the current class.
For example, the following code fragment returns the runtime Class descriptor for the class named java.lang.Thread:
Class t = Class.forName("java.lang.Thread")
A call to forName("X") causes the class named X to be initialized.
In cases where this method is called from a context where there is no caller frame on the stack (e.g. when called directly from a JNI attached thread), the system class loader is used.
className - the fully qualified name of the desired class.
Class object for the class with the specified name.
LinkageError - if the linkage fails
ExceptionInInitializerError - if the initialization provoked by this method fails
ClassNotFoundException - if the class cannot be located
Returns the
Class
object associated with the class or interface with the given string name, using the given class loader. Given the fully qualified name for a class or interface (in the same format returned by
getName
) this method attempts to locate and load the class or interface. The specified class loader is used to load the class or interface. If the parameter
loader
is null, the class is loaded through the bootstrap class loader. The class is initialized only if the
initialize
parameter is
true
and if it has not been initialized earlier.
If name denotes a primitive type or void, an attempt will be made to locate a user-defined class in the unnamed package whose name is name. Therefore, this method cannot be used to obtain any of the Class objects representing primitive types or void.
If name denotes an array class, the component type of the array class is loaded but not initialized.
For example, in an instance method the expression:
Class.forName("Foo")
is equivalent to:
Class.forName("Foo", true, this.getClass().getClassLoader())
Note that this method throws errors related to loading, linking or initializing as specified in Sections
12.2,
12.3, and
12.4of
The Java Language Specification. Note that this method does not check whether the requested class is accessible to its caller.
name - fully qualified name of the desired class
initialize - if true the class will be initialized (which implies linking). See Section 12.4 of The Java Language Specification.
loader - class loader from which the class must be loaded
LinkageError - if the linkage fails
ExceptionInInitializerError - if the initialization provoked by this method fails
ClassNotFoundException - if the class cannot be located by the specified class loader
SecurityException - if a security manager is present, and the loader is null, and the caller's class loader is not null, and the caller does not have the RuntimePermission("getClassLoader")
Returns the
Class
with the given
binary namein the given module.
This method attempts to locate and load the class or interface. It does not link the class, and does not run the class initializer. If the class is not found, this method returns null.
If the class loader of the given module defines other modules and the given name is a class defined in a different module, this method returns null after the class is loaded.
This method does not check whether the requested class is accessible to its caller.
null on failure rather than throwing a ClassNotFoundException, as is done by the forName(String, boolean, ClassLoader) method. The security check is a stack-based permission check if the caller loads a class in another module.
module - A module
name - The binary name of the class
Class object of the given name defined in the given module; null if not found.
NullPointerException - if the given module or name is null
LinkageError - if the linkage fails
SecurityException -
RuntimePermission("getClassLoader") permission is denied; orModuleReader.open(String) to read the bytes of a class file in a module.Creates a new instance of the class represented by this Class object. The class is instantiated as if by a new expression with an empty argument list. The class is initialized if it has not already been initialized.
IllegalAccessException - if the class or its nullary constructor is not accessible.
InstantiationException - if this Class represents an abstract class, an interface, an array class, a primitive type, or void; or if the class has no nullary constructor; or if the instantiation fails for some other reason.
ExceptionInInitializerError - if the initialization provoked by this method fails.
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Determines if the specified
Object
is assignment-compatible with the object represented by this
Class
. This method is the dynamic equivalent of the Java language
instanceof
operator. The method returns
true
if the specified
Object
argument is non-null and can be cast to the reference type represented by this
Class
object without raising a
ClassCastException.
It returns
false
otherwise.
Specifically, if this Class object represents a declared class, this method returns true if the specified Object argument is an instance of the represented class (or of any of its subclasses); it returns false otherwise. If this Class object represents an array class, this method returns true if the specified Object argument can be converted to an object of the array class by an identity conversion or by a widening reference conversion; it returns false otherwise. If this Class object represents an interface, this method returns true if the class or any superclass of the specified Object argument implements this interface; it returns false otherwise. If this Class object represents a primitive type, this method returns false.
obj - the object to check
obj is an instance of this class
Determines if the class or interface represented by this
Class
object is either the same as, or is a superclass or superinterface of, the class or interface represented by the specified
Class
parameter. It returns
true
if so; otherwise it returns
false
. If this
Class
object represents a primitive type, this method returns
true
if the specified
Class
parameter is exactly this
Class
object; otherwise it returns
false
.
Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this Class object via an identity conversion or via a widening reference conversion. See The Java Language Specification, sections 5.1.1 and 5.1.4, for details.
cls - the Class object to be checked
boolean value indicating whether objects of the type cls can be assigned to objects of this class
NullPointerException - if the specified Class parameter is null.
public boolean isInterface()
Determines if this Class object represents an interface type.
true if this Class object represents an interface; false otherwise.
public boolean isArray()
Determines if this Class object represents an array class.
isArray in interface TypeDescriptor.OfField<T>
true if this Class object represents an array class; false otherwise.
public boolean isPrimitive()
Determines if the specified
Class
object represents a primitive type.
There are nine predefined Class objects to represent the eight primitive types and void. These are created by the Java Virtual Machine, and have the same names as the primitive types that they represent, namely boolean, byte, char, short, int, long, float, and double.
These objects may only be accessed via the following public static final variables, and are the only Class objects for which this method returns true.
isPrimitive in interface TypeDescriptor.OfField<T>
public boolean isAnnotation()
Returns true if this
Class
object represents an annotation interface. Note that if this method returns true,
isInterface()
would also return true, as all annotation interfaces are also interfaces.
true if this Class object represents an annotation interface; false otherwise
public boolean isSynthetic()
Returns true if and only if this class has the synthetic modifier bit set.
true if and only if this class has the synthetic modifier bit set
ClassFile Structure
Returns the name of the entity (class, interface, array class, primitive type, or void) represented by this
Class
object.
If this Class object represents a class or interface, not an array class, then:
N + '/' + <suffix> where N is the binary name indicated by the class file passed to Lookup::defineHiddenClass, and <suffix> is an unqualified name.If this Class object represents an array class, then the result is a string consisting of one or more '[' characters representing the depth of the array nesting, followed by the element type as encoded using the following table:
Element types and encodings Element Type EncodingbooleanZbyteBcharCclass or interface with binary name NLN;doubleDfloatFintIlongJshortS
If this Class object represents a primitive type or void, then the result is a string with the same spelling as the Java language keyword which corresponds to the primitive type or void.
Examples:
String.class.getName()
returns "java.lang.String"
byte.class.getName()
returns "byte"
(new Object[3]).getClass().getName()
returns "[Ljava.lang.Object;"
(new int[3][4][5][6][7][8][9]).getClass().getName()
returns "[[[[[[[I"
Class object.
If this Class object represents a primitive type or void, null is returned.
Class object.
SecurityException - if a security manager is present, and the caller's class loader is not null and is not the same as or an ancestor of the class loader for the class whose class loader is requested, and the caller does not have the RuntimePermission("getClassLoader")
Returns the module that this class or interface is a member of. If this class represents an array type then this method returns the
Module
for the element type. If this class represents a primitive type or void, then the
Module
object for the
java.base
module is returned. If this class is in an unnamed module then the
unnamedModule
of the class loader for this class is returned.
Returns an array of TypeVariable objects that represent the type variables declared by the generic declaration represented by this GenericDeclaration object, in declaration order. Returns an array of length 0 if the underlying generic declaration declares no type variables.
getTypeParameters in interface GenericDeclaration
TypeVariable objects that represent the type variables declared by this generic declaration
GenericSignatureFormatError - if the generic signature of this generic declaration does not conform to the format specified in section 4.7.9 of The Java Virtual Machine Specification
()
Returns the Class representing the direct superclass of the entity (class, interface, primitive type or void) represented by this Class. If this Class represents either the Object class, an interface, a primitive type, or void, then null is returned. If this Class object represents an array class then the Class object representing the Object class is returned.
Class object
()
Returns the
Type
representing the direct superclass of the entity (class, interface, primitive type or void) represented by this
Class
object.
If the superclass is a parameterized type, the Type object returned must accurately reflect the actual type arguments used in the source code. The parameterized type representing the superclass is created if it had not been created before. See the declaration of ParameterizedType for the semantics of the creation process for parameterized types. If this Class object represents either the Object class, an interface, a primitive type, or void, then null is returned. If this Class object represents an array class then the Class object representing the Object class is returned.
Class object
GenericSignatureFormatError - if the generic class signature does not conform to the format specified in section 4.7.9 of The Java Virtual Machine Specification
TypeNotPresentException - if the generic superclass refers to a non-existent type declaration
MalformedParameterizedTypeException - if the generic superclass refers to a parameterized type that cannot be instantiated for any reason
If this class represents an array type, a primitive type or void, this method returns null.
()
Returns the fully qualified package name.
If this class is a top level class, then this method returns the fully qualified name of the package that the class is a member of, or the empty string if the class is in an unnamed package.
If this class is a member class, then this method is equivalent to invoking getPackageName() on the enclosing class.
If this class is a local class or an anonymous class, then this method is equivalent to invoking getPackageName() on the declaring class of the enclosing method or enclosing constructor.
If this class represents an array type then this method returns the package name of the element type. If this class represents a primitive type or void then the package name "java.lang" is returned.
()
Returns the interfaces directly implemented by the class or interface represented by this
Class
object.
If this Class object represents a class, the return value is an array containing objects representing all interfaces directly implemented by the class. The order of the interface objects in the array corresponds to the order of the interface names in the implements clause of the declaration of the class represented by this Class object. For example, given the declaration:
class Shimmer implements FloorWax, DessertTopping { ... }
suppose the value of
s
is an instance of
Shimmer
; the value of the expression:
s.getClass().getInterfaces()[0]
is the
Class
object that represents interface
FloorWax
; and the value of:
s.getClass().getInterfaces()[1]
is the
Class
object that represents interface
DessertTopping
.
If this Class object represents an interface, the array contains objects representing all interfaces directly extended by the interface. The order of the interface objects in the array corresponds to the order of the interface names in the extends clause of the declaration of the interface represented by this Class object.
If this Class object represents a class or interface that implements no interfaces, the method returns an array of length 0.
If this Class object represents a primitive type or void, the method returns an array of length 0.
If this Class object represents an array type, the interfaces Cloneable and java.io.Serializable are returned in that order.
()
Returns the
Type
s representing the interfaces directly implemented by the class or interface represented by this
Class
object.
If a superinterface is a parameterized type, the Type object returned for it must accurately reflect the actual type arguments used in the source code. The parameterized type representing each superinterface is created if it had not been created before. See the declaration of ParameterizedType for the semantics of the creation process for parameterized types.
If this Class object represents a class, the return value is an array containing objects representing all interfaces directly implemented by the class. The order of the interface objects in the array corresponds to the order of the interface names in the implements clause of the declaration of the class represented by this Class object.
If this Class object represents an interface, the array contains objects representing all interfaces directly extended by the interface. The order of the interface objects in the array corresponds to the order of the interface names in the extends clause of the declaration of the interface represented by this Class object.
If this Class object represents a class or interface that implements no interfaces, the method returns an array of length 0.
If this Class object represents a primitive type or void, the method returns an array of length 0.
If this Class object represents an array type, the interfaces Cloneable and java.io.Serializable are returned in that order.
GenericSignatureFormatError - if the generic class signature does not conform to the format specified in section 4.7.9 of The Java Virtual Machine Specification
TypeNotPresentException - if any of the generic superinterfaces refers to a non-existent type declaration
MalformedParameterizedTypeException - if any of the generic superinterfaces refer to a parameterized type that cannot be instantiated for any reason
()
Returns the Class representing the component type of an array. If this class does not represent an array class this method returns null.
Class representing the component type of this class if this class is an array
public int getModifiers()
Returns the Java language modifiers for this class or interface, encoded in an integer. The modifiers consist of the Java Virtual Machine's constants for
public
,
protected
,
private
,
final
,
static
,
abstract
and
interface
; they should be decoded using the methods of class
Modifier
.
If the underlying class is an array class:
public, private and protected modifiers are the same as those of its component typeabstract and final modifiers are always truefalse, even when the component type is an interfaceIf this
Class
object represents a primitive type or void, its
public
,
abstract
, and
final
modifiers are always
true
. For
Class
objects representing void, primitive types, and arrays, the values of other modifiers are
false
other than as specified above.
The modifier encodings are defined in section 4.1 of The Java Virtual Machine Specification.
int representing the modifiers for this class
ClassFile Structure
Returns an unmodifiable set of the
access flagsfor this class, possibly empty.
If the underlying class is an array class:
PUBLIC, PRIVATE and PROTECTED access flags are the same as those of its component typeABSTRACT and FINAL flags are presentINTERFACE flag is absent, even when the component type is an interfaceIf this
Class
object represents a primitive type or void, the flags are
PUBLIC
,
ABSTRACT
, and
FINAL
. For
Class
objects representing void, primitive types, and arrays, access flags are absent other than as specified above.
Gets the signers of this class.
Class object represents a primitive type or void.
If this
Class
object represents a local or anonymous class within a method, returns a
Method
object representing the immediately enclosing method of the underlying class. Returns
null
otherwise. In particular, this method returns
null
if the underlying class is a local or anonymous class immediately enclosed by a class or interface declaration, instance initializer or static initializer.
null.
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the methods within the enclosing classs.checkPackageAccess() denies access to the package of the enclosing classIf this
Class
object represents a local or anonymous class within a constructor, returns a
Constructor
object representing the immediately enclosing constructor of the underlying class. Returns
null
otherwise. In particular, this method returns
null
if the underlying class is a local or anonymous class immediately enclosed by a class or interface declaration, instance initializer or static initializer.
null.
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the constructors within the enclosing classs.checkPackageAccess() denies access to the package of the enclosing classIf the class or interface represented by this Class object is a member of another class, returns the Class object representing the class in which it was declared. This method returns null if this class or interface is not a member of any other class. If this Class object represents an array class, a primitive type, or void, then this method returns null.
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the declaring class and invocation of s.checkPackageAccess() denies access to the package of the declaring class
Returns the immediately enclosing class of the underlying class. If the underlying class is a top level class this method returns null.
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the enclosing class and invocation of s.checkPackageAccess() denies access to the package of the enclosing class
()
Returns the simple name of the underlying class as given in the source code. An empty string is returned if the underlying class is
anonymous. A
synthetic class, one not present in source code, can have a non-empty name including special characters, such as "
$
".
The simple name of an array class is the simple name of the component type with "[]" appended. In particular the simple name of an array class whose component type is anonymous is "[]".
Return an informative string for the name of this class or interface.
getTypeName in interface Type
()
Returns the canonical name of the underlying class as defined by
The Java Language Specification. Returns
null
if the underlying class does not have a canonical name. Classes without canonical names include:
The canonical name for a primitive class is the keyword for the corresponding primitive type (
byte
,
short
,
char
,
int
, and so on).
An array type has a canonical name if and only if its component type has a canonical name. When an array type has a canonical name, it is equal to the canonical name of the component type followed by "[]".
null otherwise.
public boolean isAnonymousClass()
Returns true if and only if the underlying class is an anonymous class.
true if and only if this class is an anonymous class.
public boolean isLocalClass()
Returns true if and only if the underlying class is a local class.
true if and only if this class is a local class.
public boolean isMemberClass()
Returns true if and only if the underlying class is a member class.
true if and only if this class is a member class.
()
Returns an array containing Class objects representing all the public classes and interfaces that are members of the class represented by this Class object. This includes public class and interface members inherited from superclasses and public class and interface members declared by the class. This method returns an array of length 0 if this Class object has no public member classes or interfaces. This method also returns an array of length 0 if this Class object represents a primitive type, an array class, or void.
Class objects representing the public members of this class
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns an array containing
Field
objects reflecting all the accessible public fields of the class or interface represented by this
Class
object.
If this Class object represents a class or interface with no accessible public fields, then this method returns an array of length 0.
If this Class object represents a class, then this method returns the public fields of the class and of all its superclasses and superinterfaces.
If this Class object represents an interface, then this method returns the fields of the interface and of all its superinterfaces.
If this Class object represents an array type, a primitive type, or void, then this method returns an array of length 0.
The elements in the returned array are not sorted and are not in any particular order.
Field objects representing the public fields
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns an array containing
Method
objects reflecting all the public methods of the class or interface represented by this
Class
object, including those declared by the class or interface and those inherited from superclasses and superinterfaces.
If this Class object represents an array type, then the returned array has a Method object for each of the public methods inherited by the array type from Object. It does not contain a Method object for clone().
If this Class object represents an interface then the returned array does not contain any implicitly declared methods from Object. Therefore, if no methods are explicitly declared in this interface or any of its superinterfaces then the returned array has length 0. (Note that a Class object which represents a class always has public methods, inherited from Object.)
The returned array never contains methods with names "<init>" or "<clinit>".
The elements in the returned array are not sorted and are not in any particular order.
Generally, the result is computed as with the following 4 step algorithm. Let C be the class or interface represented by this Class object:
getDeclaredMethods() and filtered to include only public methods.Object, then include the result of invoking this algorithm recursively on the superclass of C.Method objects representing the public methods of this class
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns an array containing Constructor objects reflecting all the public constructors of the class represented by this Class object. An array of length 0 is returned if the class has no public constructors, or if the class is an array class, or if the class reflects a primitive type or void.
Constructor<T> objects (that is an array of constructors from this class), the return type of this method is Constructor<?>[] and not Constructor<T>[] as might be expected. This less informative return type is necessary since after being returned from this method, the array could be modified to hold Constructor objects for different classes, which would violate the type guarantees of Constructor<T>[].
Constructor objects representing the public constructors of this class
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns a
Field
object that reflects the specified public member field of the class or interface represented by this
Class
object. The
name
parameter is a
String
specifying the simple name of the desired field.
The field to be reflected is determined by the algorithm that follows. Let C be the class or interface represented by this Class object:
NoSuchFieldException is thrown.If this Class object represents an array type, then this method does not find the length field of the array type.
name - the field name
Field object of this class specified by name
NoSuchFieldException - if a field with the specified name is not found.
NullPointerException - if name is null
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns a
Method
object that reflects the specified public member method of the class or interface represented by this
Class
object. The
name
parameter is a
String
specifying the simple name of the desired method. The
parameterTypes
parameter is an array of
Class
objects that identify the method's formal parameter types, in declared order. If
parameterTypes
is
null
, it is treated as if it were an empty array.
If this Class object represents an array type, then this method finds any public method inherited by the array type from Object except method clone().
If this Class object represents an interface then this method does not find any implicitly declared method from Object. Therefore, if no methods are explicitly declared in this interface or any of its superinterfaces, then this method does not find any method.
This method does not find any method with name "<init>" or "<clinit>".
Generally, the method to be reflected is determined by the 4 step algorithm that follows. Let C be the class or interface represented by this Class object:
getDeclaredMethods() and filtered to include only public methods that match given name and parameterTypesObject, then include the result of invoking this algorithm recursively on the superclass of C.isAssignableFrom(java.lang.Class<?>)(S.class).name - the name of the method
parameterTypes - the list of parameters
Method object that matches the specified name and parameterTypes
NoSuchMethodException - if a matching method is not found or if the name is "<init>"or "<clinit>".
NullPointerException - if name is null
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns a
Constructor
object that reflects the specified public constructor of the class represented by this
Class
object. The
parameterTypes
parameter is an array of
Class
objects that identify the constructor's formal parameter types, in declared order. If this
Class
object represents an inner class declared in a non-static context, the formal parameter types include the explicit enclosing instance as the first parameter.
The constructor to reflect is the public constructor of the class represented by this Class object whose formal parameter types match those specified by parameterTypes.
parameterTypes - the parameter array
Constructor object of the public constructor that matches the specified parameterTypes
NoSuchMethodException - if a matching constructor is not found, including when this Class object represents an interface, a primitive type, an array class, or void.
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class.
Returns an array of Class objects reflecting all the classes and interfaces declared as members of the class represented by this Class object. This includes public, protected, default (package) access, and private classes and interfaces declared by the class, but excludes inherited classes and interfaces. This method returns an array of length 0 if the class declares no classes or interfaces as members, or if this Class object represents a primitive type, an array class, or void.
Class objects representing all the declared members of this class
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared classes within this classs.checkPackageAccess() denies access to the package of this classReturns an array of
Field
objects reflecting all the fields declared by the class or interface represented by this
Class
object. This includes public, protected, default (package) access, and private fields, but excludes inherited fields.
If this Class object represents a class or interface with no declared fields, then this method returns an array of length 0.
If this Class object represents an array type, a primitive type, or void, then this method returns an array of length 0.
The elements in the returned array are not sorted and are not in any particular order.
Field objects representing all the declared fields of this class
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared fields within this classs.checkPackageAccess() denies access to the package of this classReturns an array of
RecordComponent
objects representing all the record components of this record class, or
null
if this class is not a record class.
The components are returned in the same order that they are declared in the record header. The array is empty if this record class has no components. If the class is not a record class, that is isRecord() returns false, then this method returns null. Conversely, if isRecord() returns true, then this method returns a non-null value.
The following method can be used to find the record canonical constructor:
static <T extends Record> Constructor<T> getCanonicalConstructor(Class<T> cls)
throws NoSuchMethodException {
Class<?>[] paramTypes =
Arrays.stream(cls.getRecordComponents())
.map(RecordComponent::getType)
.toArray(Class<?>[]::new);
return cls.getDeclaredConstructor(paramTypes);
}RecordComponent objects representing all the record components of this record class, or null if this class is not a record class
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared methods within this classs.checkPackageAccess() denies access to the package of this classReturns an array containing
Method
objects reflecting all the declared methods of the class or interface represented by this
Class
object, including public, protected, default (package) access, and private methods, but excluding inherited methods. The declared methods may include methods
notin the source of the class or interface, including
bridge methodsand other
syntheticmethods added by compilers.
If this Class object represents a class or interface that has multiple declared methods with the same name and parameter types, but different return types, then the returned array has a Method object for each such method.
If this Class object represents a class or interface that has a class initialization method <clinit>, then the returned array does not have a corresponding Method object.
If this Class object represents a class or interface with no declared methods, then the returned array has length 0.
If this Class object represents an array type, a primitive type, or void, then the returned array has length 0.
The elements in the returned array are not sorted and are not in any particular order.
Method objects representing all the declared methods of this class
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared methods within this classs.checkPackageAccess() denies access to the package of this classReturns an array of
Constructor
objects reflecting all the constructors implicitly or explicitly declared by the class represented by this
Class
object. These are public, protected, default (package) access, and private constructors. The elements in the array returned are not sorted and are not in any particular order. If the class has a default constructor (JLS
8.8.9), it is included in the returned array. If a record class has a canonical constructor (JLS
8.10.4.1,
8.10.4.2), it is included in the returned array. This method returns an array of length 0 if this
Class
object represents an interface, a primitive type, an array class, or void.
Constructor objects representing all the declared constructors of this class
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared constructors within this classs.checkPackageAccess() denies access to the package of this classReturns a
Field
object that reflects the specified declared field of the class or interface represented by this
Class
object. The
name
parameter is a
String
that specifies the simple name of the desired field.
If this Class object represents an array type, then this method does not find the length field of the array type.
name - the name of the field
Field object for the specified field in this class
NoSuchFieldException - if a field with the specified name is not found.
NullPointerException - if name is null
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared fields.checkPackageAccess() denies access to the package of this classReturns a
Method
object that reflects the specified declared method of the class or interface represented by this
Class
object. The
name
parameter is a
String
that specifies the simple name of the desired method, and the
parameterTypes
parameter is an array of
Class
objects that identify the method's formal parameter types, in declared order. If more than one method with the same parameter types is declared in a class, and one of these methods has a return type that is more specific than any of the others, that method is returned; otherwise one of the methods is chosen arbitrarily. If the name is "<init>"or "<clinit>" a
NoSuchMethodException
is raised.
If this Class object represents an array type, then this method does not find the clone() method.
name - the name of the method
parameterTypes - the parameter array
Method object for the method of this class matching the specified name and parameters
NoSuchMethodException - if a matching method is not found.
NullPointerException - if name is null
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared methods.checkPackageAccess() denies access to the package of this classReturns a Constructor object that reflects the specified constructor of the class represented by this Class object. The parameterTypes parameter is an array of Class objects that identify the constructor's formal parameter types, in declared order. If this Class object represents an inner class declared in a non-static context, the formal parameter types include the explicit enclosing instance as the first parameter.
parameterTypes - the parameter array
Constructor object for the constructor with the specified parameter list
NoSuchMethodException - if a matching constructor is not found, including when this Class object represents an interface, a primitive type, an array class, or void.
SecurityException - If a security manager, s, is present and any of the following conditions is met:
s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared constructors.checkPackageAccess() denies access to the package of this classFinds a resource with a given name.
If this class is in a named Module then this method will attempt to find the resource in the module. This is done by delegating to the module's class loader findResource(String,String) method, invoking it with the module name and the absolute name of the resource. Resources in named modules are subject to the rules for encapsulation specified in the Module getResourceAsStream method and so this method returns null when the resource is a non-".class" resource in a package that is not open to the caller's module.
Otherwise, if this class is not in a named module then the rules for searching resources associated with a given class are implemented by the defining class loader of the class. This method delegates to this Class object's class loader. If this Class object was loaded by the bootstrap class loader, the method delegates to ClassLoader.getSystemResourceAsStream(java.lang.String).
Before delegation, an absolute resource name is constructed from the given resource name using this algorithm:
name begins with a '/' ('\u002f'), then the absolute name of the resource is the portion of the name following the '/'.
modified_package_name/name
Where the modified_package_name is the package name of this object with '/' substituted for '.' ('\u002e').
name - name of the desired resource
InputStream object; null if no resource with this name is found, the resource is in a package that is not open to at least the caller module, or access to the resource is denied by the security manager.
NullPointerException - If name is null
Finds a resource with a given name.
If this class is in a named Module then this method will attempt to find the resource in the module. This is done by delegating to the module's class loader findResource(String,String) method, invoking it with the module name and the absolute name of the resource. Resources in named modules are subject to the rules for encapsulation specified in the Module getResourceAsStream method and so this method returns null when the resource is a non-".class" resource in a package that is not open to the caller's module.
Otherwise, if this class is not in a named module then the rules for searching resources associated with a given class are implemented by the defining class loader of the class. This method delegates to this Class object's class loader. If this Class object was loaded by the bootstrap class loader, the method delegates to ClassLoader.getSystemResource(java.lang.String).
Before delegation, an absolute resource name is constructed from the given resource name using this algorithm:
name begins with a '/' ('\u002f'), then the absolute name of the resource is the portion of the name following the '/'.
modified_package_name/name
Where the modified_package_name is the package name of this object with '/' substituted for '.' ('\u002e').
name - name of the desired resource
URL object; null if no resource with this name is found, the resource cannot be located by a URL, the resource is in a package that is not open to at least the caller module, or access to the resource is denied by the security manager.
NullPointerException - If name is null
Returns the ProtectionDomain of this class. If there is a security manager installed, this method first calls the security manager's checkPermission method with a RuntimePermission("getProtectionDomain") permission to ensure it's ok to get the ProtectionDomain.
SecurityException - if a security manager exists and its checkPermission method doesn't allow getting the ProtectionDomain.
public boolean desiredAssertionStatus()
Returns the assertion status that would be assigned to this class if it were to be initialized at the time this method is invoked. If this class has had its assertion status set, the most recent setting will be returned; otherwise, if any package default assertion status pertains to this class, the most recent setting for the most specific pertinent package default assertion status is returned; otherwise, if this class is not a system class (i.e., it has a class loader) its class loader's default assertion status is returned; otherwise, the system class default assertion status is returned.
public boolean isEnum()
Returns true if and only if this class was declared as an enum in the source code. Note that
Enum
is not itself an enum class. Also note that if an enum constant is declared with a class body, the class of that enum constant object is an anonymous class and
notthe class of the declaring enum class. The
Enum.getDeclaringClass()
method of an enum constant can be used to get the class of the enum class declaring the constant.
public boolean isRecord()
Returns
true
if and only if this class is a record class.
The direct superclass of a record class is java.lang.Record. A record class is final. A record class has (possibly zero) record components; getRecordComponents() returns a non-null but possibly empty value for a record.
Note that class Record is not a record class and thus invoking this method on class Record returns false.
()
Returns the elements of this enum class or null if this Class object does not represent an enum class.
Class object in the order they're declared, or null if this Class object does not represent an enum class
Casts an object to the class or interface represented by this Class object.
obj - the object to be cast
ClassCastException - if the object is not null and is not assignable to the type T.
Casts this
Class
object to represent a subclass of the class represented by the specified class object. Checks that the cast is valid, and throws a
ClassCastException
if it is not. If this method succeeds, it always returns a reference to this
Class
object.
This method is useful when a client needs to "narrow" the type of a Class object to pass it to an API that restricts the Class objects that it is willing to accept. A cast would generate a compile-time warning, as the correctness of the cast could not be checked at runtime (because generic types are implemented by erasure).
U - the type to cast this Class object to
clazz - the class of the type to cast this Class object to
Class object, cast to represent a subclass of the specified class object.
ClassCastException - if this Class object does not represent a subclass of the specified class (here "subclass" includes the class itself).
Returns this element's annotation for the specified type if such an annotation is
present, else null.
Note that any annotation returned by this method is a declaration annotation.
getAnnotation in interface AnnotatedElement
A - the type of the annotation to query for and return if present
annotationClass - the Class object corresponding to the annotation type
NullPointerException - if the given annotation class is null
Returns true if an annotation for the specified type is
presenton this element, else false. This method is designed primarily for convenient access to marker annotations.
The truth value returned by this method is equivalent to: getAnnotation(annotationClass) != null
isAnnotationPresent in interface AnnotatedElement
annotationClass - the Class object corresponding to the annotation type
NullPointerException - if the given annotation class is null
Returns annotations that are
associatedwith this element. If there are no annotations
associatedwith this element, the return value is an array of length 0. The difference between this method and
AnnotatedElement.getAnnotation(Class)
is that this method detects if its argument is a
repeatable annotation type(JLS
9.6), and if so, attempts to find one or more annotations of that type by "looking through" a container annotation. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are declaration annotations.
getAnnotationsByType in interface AnnotatedElement
A - the type of the annotation to query for and return if present
annotationClass - the Class object corresponding to the annotation type
NullPointerException - if the given annotation class is null
Returns annotations that are
presenton this element. If there are no annotations
presenton this element, the return value is an array of length 0. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are declaration annotations.
getAnnotations in interface AnnotatedElement
Returns this element's annotation for the specified type if such an annotation is
directly present, else null. This method ignores inherited annotations. (Returns null if no annotations are directly present on this element.)
Note that any annotation returned by this method is a declaration annotation.
getDeclaredAnnotation in interface AnnotatedElement
A - the type of the annotation to query for and return if directly present
annotationClass - the Class object corresponding to the annotation type
NullPointerException - if the given annotation class is null
Returns this element's annotation(s) for the specified type if such annotations are either
directly presentor
indirectly present. This method ignores inherited annotations. If there are no specified annotations directly or indirectly present on this element, the return value is an array of length 0. The difference between this method and
AnnotatedElement.getDeclaredAnnotation(Class)
is that this method detects if its argument is a
repeatable annotation type(JLS
9.6), and if so, attempts to find one or more annotations of that type by "looking through" a container annotation if one is present. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are declaration annotations.
getDeclaredAnnotationsByType in interface AnnotatedElement
A - the type of the annotation to query for and return if directly or indirectly present
annotationClass - the Class object corresponding to the annotation type
NullPointerException - if the given annotation class is null
Returns annotations that are
directly presenton this element. This method ignores inherited annotations. If there are no annotations
directly presenton this element, the return value is an array of length 0. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are declaration annotations.
getDeclaredAnnotations in interface AnnotatedElement
Returns an
AnnotatedType
object that represents the use of a type to specify the superclass of the entity represented by this
Class
object. (The
useof type Foo to specify the superclass in '... extends Foo' is distinct from the
declarationof class Foo.)
If this Class object represents a class whose declaration does not explicitly indicate an annotated superclass, then the return value is an AnnotatedType object representing an element with no annotations.
If this Class represents either the Object class, an interface type, an array type, a primitive type, or void, the return value is null.
Returns an array of
AnnotatedType
objects that represent the use of types to specify superinterfaces of the entity represented by this
Class
object. (The
useof type Foo to specify a superinterface in '... implements Foo' is distinct from the
declarationof interface Foo.)
If this Class object represents a class, the return value is an array containing objects representing the uses of interface types to specify interfaces implemented by the class. The order of the objects in the array corresponds to the order of the interface types used in the 'implements' clause of the declaration of this Class object.
If this Class object represents an interface, the return value is an array containing objects representing the uses of interface types to specify interfaces directly extended by the interface. The order of the objects in the array corresponds to the order of the interface types used in the 'extends' clause of the declaration of this Class object.
If this Class object represents a class or interface whose declaration does not explicitly indicate any annotated superinterfaces, the return value is an array of length 0.
If this Class object represents either the Object class, an array type, a primitive type, or void, the return value is an array of length 0.
()
Returns the nest host of the
nestto which the class or interface represented by this
Class
object belongs. Every class and interface belongs to exactly one nest. If the nest host of this class or interface has previously been determined, then this method returns the nest host. If the nest host of this class or interface has not previously been determined, then this method determines the nest host using the algorithm of JVMS 5.4.4, and returns it. Often, a class or interface belongs to a nest consisting only of itself, in which case this method returns
this
to indicate that the class or interface is the nest host.
If this Class object represents a primitive type, an array type, or void, then this method returns this, indicating that the represented entity belongs to the nest consisting only of itself, and is the nest host.
SecurityException - If the returned class is not the current class, and if a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for the returned class and invocation of s.checkPackageAccess() denies access to the package of the returned class
NestHost Attribute
NestMembers Attribute
Determines if the given
Class
is a nestmate of the class or interface represented by this
Class
object. Two classes or interfaces are nestmates if they have the same
nest host.
c - the class to check
true if this class and c are members of the same nest; and false otherwise.
()
Returns an array containing
Class
objects representing all the classes and interfaces that are members of the nest to which the class or interface represented by this
Class
object belongs. First, this method obtains the
nest host,
H
, of the nest to which the class or interface represented by this
Class
object belongs. The zeroth element of the returned array is
H
. Then, for each class or interface
C
which is recorded by
H
as being a member of its nest, this method attempts to obtain the
Class
object for
C
(using
the defining class loaderof the current
Class
object), and then obtains the
nest hostof the nest to which
C
belongs. The classes and interfaces which are recorded by
H
as being members of its nest, and for which
H
can be determined as their nest host, are indicated by subsequent elements of the returned array. The order of such elements is unspecified. Duplicates are permitted.
If this Class object represents a primitive type, an array type, or void, then this method returns a single-element array containing this.
NestMembers attribute, and not any hidden classes that were added to the nest via Lookup::defineHiddenClass.
SecurityException - If any returned class is not the current class, and if a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for that returned class and invocation of s.checkPackageAccess() denies access to the package of that returned class
NestHost Attribute
NestMembers Attribute
()
Returns the descriptor string of the entity (class, interface, array class, primitive type, or
void
) represented by this
Class
object.
If this Class object represents a class or interface, not an array class, then:
ClassDesc::ofDescriptor with the result descriptor string produces a ClassDesc describing this class or interface.where N is the binary name encoded in internal form indicated by the"L" +N+ "." + <suffix> + ";"
class file passed to Lookup::defineHiddenClass, and <suffix> is an unqualified name. A hidden class or interface has no nominal descriptor. The result string is not a type descriptor.If this Class object represents an array class, then the result is a string consisting of one or more '[' characters representing the depth of the array nesting, followed by the descriptor string of the element type.
ClassDesc::ofDescriptor with the result descriptor string produces a ClassDesc describing this array class.If this Class object represents a primitive type or void, then the result is a field descriptor string which is a one-letter code corresponding to a primitive type or void ("B", "C", "D", "F", "I", "J", "S", "Z", "V") (JVMS 4.3.2).
descriptorString in interface TypeDescriptor
forName(java.lang.String); distinct classes which share a common name but have different class loaders will have identical descriptor strings.
Class object
()
Returns the component type of this Class, if it describes an array type, or null otherwise.
componentType in interface TypeDescriptor.OfField<T>
getComponentType().
Class describing the component type, or null if this Class does not describe an array type
()
Returns a
Class
for an array type whose component type is described by this
Class.
arrayType in interface TypeDescriptor.OfField<T>
Class describing the array type
UnsupportedOperationException - if this component type is void or if the number of dimensions of the resulting array type would exceed 255.
CONSTANT_Class_info Structure
Returns a nominal descriptor for this instance, if one can be constructed, or an empty
Optional
if one cannot be.
describeConstable in interface Constable
Optional containing the resulting nominal descriptor, or an empty Optional if one cannot be constructed.
public boolean isHidden()
Returns true if and only if the underlying class is a hidden class.
true if and only if this class is a hidden class.
()
Returns an array containing
Class
objects representing the direct subinterfaces or subclasses permitted to extend or implement this class or interface if it is sealed. The order of such elements is unspecified. The array is empty if this sealed class or interface has no permitted subclass. If this
Class
object represents a primitive type,
void
, an array type, or a class or interface that is not sealed, that is
isSealed()
returns
false
, then this method returns
null
. Conversely, if
isSealed()
returns
true
, then this method returns a non-null value. For each class or interface
C
which is recorded as a permitted direct subinterface or subclass of this class or interface, this method attempts to obtain the
Class
object for
C
(using
the defining class loaderof the current
Class
object). The
Class
objects which can be obtained and which are direct subinterfaces or subclasses of this class or interface, are indicated by elements of the returned array. If a
Class
object cannot be obtained, it is silently ignored, and not included in the result array.
Class objects of the permitted subclasses of this class or interface, or null if this class or interface is not sealed.
SecurityException - If a security manager, s, is present and the caller's class loader is not the same as or an ancestor of the class loader for that returned class and invocation of s.checkPackageAccess() denies access to the package of any class in the returned array.
public boolean isSealed()
Returns
true
if and only if this
Class
object represents a sealed class or interface. If this
Class
object represents a primitive type,
void
, or an array type, this method returns
false
. A sealed class or interface has (possibly zero) permitted subclasses;
getPermittedSubclasses()
returns a non-null but possibly empty value for a sealed class or interface.
true if and only if this Class object represents a sealed class or interface.
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