Module java.base
Package java.lang.reflect

# Class Executable

java.lang.Object
java.lang.reflect.AccessibleObject
java.lang.reflect.Executable

All Implemented Interfaces:
  `AnnotatedElement`, `GenericDeclaration`, `Member`

Direct Known Subclasses:
  `Constructor`, `Method`

public abstract sealed class Executable extends AccessibleObject implements Member, GenericDeclaration permits Constructor<T>, Method
A shared superclass for the common functionality of `Method` and `Constructor`.

Since:
  1.8

## Field Summary

### Fields declared in interface java.lang.reflect.Member

`DECLARED, PUBLIC`

## Method Summary

Modifier and Type
Method
Description
`Set<AccessFlag>`
`accessFlags()`
Returns an unmodifiable set of the access flags for the executable represented by this object, possibly empty.
`AnnotatedType[]`
`getAnnotatedExceptionTypes()`
Returns an array of `AnnotatedType` objects that represent the use of types to specify the declared exceptions of the method/constructor represented by this Executable.
`AnnotatedType[]`
`getAnnotatedParameterTypes()`
Returns an array of `AnnotatedType` objects that represent the use of types to specify formal parameter types of the method/constructor represented by this Executable.
`AnnotatedType`
`getAnnotatedReceiverType()`
Returns an `AnnotatedType` object that represents the use of a type to specify the receiver type of the method/constructor represented by this `Executable` object.
`abstract AnnotatedType`
`getAnnotatedReturnType()`
Returns an `AnnotatedType` object that represents the use of a type to specify the return type of the method/constructor represented by this Executable.
`<T extends Annotation>
T`
`getAnnotation(Class<T> annotationClass)`
Returns this element's annotation for the specified type if such an annotation is present, else null.
`<T extends Annotation>
T[]`
`getAnnotationsByType(Class<T> annotationClass)`
Returns annotations that are associated with this element.
`Annotation[]`
`getDeclaredAnnotations()`
Returns annotations that are directly present on this element.
`abstract Class<?>`
`getDeclaringClass()`
Returns the `Class` object representing the class or interface that declares the executable represented by this object.
`abstract Class<?>[]`
`getExceptionTypes()`
Returns an array of `Class` objects that represent the types of exceptions declared to be thrown by the underlying executable represented by this object.
`Type[]`
`getGenericExceptionTypes()`
Returns an array of `Type` objects that represent the exceptions declared to be thrown by this executable object.
`Type[]`
`getGenericParameterTypes()`
Returns an array of `Type` objects that represent the formal parameter types, in declaration order, of the executable represented by this object.
`abstract int`
`getModifiers()`
Returns the Java language modifiers for the executable represented by this object.
`abstract String`
`getName()`
Returns the name of the executable represented by this object.
`abstract Annotation[][]`
`getParameterAnnotations()`
Returns an array of arrays of `Annotation`s that represent the annotations on the formal parameters, in declaration order, of the `Executable` represented by this object.
`abstract int`
`getParameterCount()`
Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object.
`Parameter[]`
`getParameters()`
Returns an array of `Parameter` objects representing all the parameters to the underlying executable represented by this object.
`abstract Class<?>[]`
`getParameterTypes()`
Returns an array of `Class` objects that represent the formal parameter types, in declaration order, of the executable represented by this object.
`abstract TypeVariable<?>[]`
`getTypeParameters()`
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`
`isSynthetic()`
Returns `true` if this executable is a synthetic construct; returns `false` otherwise.
`boolean`
`isVarArgs()`
Returns `true` if this executable was declared to take a variable number of arguments; returns `false` otherwise.
`abstract String`
`toGenericString()`
Returns a string describing this `Executable`, including any type parameters.

### Methods declared in class java.lang.reflect.AccessibleObject

`canAccess, getAnnotations, getDeclaredAnnotation, getDeclaredAnnotations, getDeclaredAnnotationsByType, isAccessible, isAnnotationPresent, setAccessible, setAccessible, trySetAccessible`

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

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

### Methods declared in interface java.lang.reflect.AnnotatedElement

`getAnnotations, getDeclaredAnnotation, getDeclaredAnnotationsByType, isAnnotationPresent`

## Method Details

### getDeclaringClass

public abstract Class<?> getDeclaringClass()
Returns the `Class` object representing the class or interface that declares the executable represented by this object.

Specified by:
  `getDeclaringClass` in interface `Member`
Returns:
  an object representing the declaring class of the underlying member

### getName

public abstract String getName()
Returns the name of the executable represented by this object.

Specified by:
  `getName` in interface `Member`
Returns:
  the simple name of the underlying member

### getModifiers

public abstract int getModifiers()
Returns the Java language modifiers for the executable represented by this object.

Specified by:
  `getModifiers` in interface `Member`
Returns:
  the Java language modifiers for the executable represented by this object
See Also:
  - `accessFlags()`

### accessFlags

public Set<AccessFlag> accessFlags()
Returns an unmodifiable set of the access flags for the executable represented by this object, possibly empty.

Specified by:
  `accessFlags` in interface `Member`
Returns:
  an unmodifiable set of the access flags for the executable represented by this object, possibly empty
See Java Virtual Machine Specification:
  4.6 Methods
Since:
  20
See Also:
  - `getModifiers()`

### getTypeParameters

public abstract TypeVariable<?>[] getTypeParameters()
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.

Specified by:
  `getTypeParameters` in interface `GenericDeclaration`
Returns:
  an array of `TypeVariable` objects that represent the type variables declared by this generic declaration
Throws:
  `GenericSignatureFormatError` - if the generic signature of this generic declaration does not conform to the format specified in The Java Virtual Machine Specification

### getParameterTypes

public abstract Class<?>[] getParameterTypes()
Returns an array of `Class` objects that represent the formal parameter types, in declaration order, of the executable represented by this object. Returns an array of length 0 if the underlying executable takes no parameters. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones.

Returns:
  the parameter types for the executable this object represents

### getParameterCount

public abstract int getParameterCount()
Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object.

Returns:
  The number of formal parameters for the executable this object represents

### getGenericParameterTypes

public Type[] getGenericParameterTypes()
Returns an array of `Type` objects that represent the formal parameter types, in declaration order, of the executable represented by this object. An array of length 0 is returned if the underlying executable takes no parameters. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones. Also note that as a modeling artifact, the number of returned parameters can differ depending on whether or not generic information is present. If generic information is present, only parameters explicitly present in the source will be returned; if generic information is not present, implicit and synthetic parameters may be returned as well.

If a formal parameter type is a parameterized type, the `Type` object returned for it must accurately reflect the actual type arguments used in the source code.

If a formal parameter type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

Returns:
  an array of `Type`s that represent the formal parameter types of the underlying executable, in declaration order
Throws:
  `GenericSignatureFormatError` - if the generic method signature does not conform to the format specified in The Java Virtual Machine Specification
  `TypeNotPresentException` - if any of the parameter types of the underlying executable refers to a non-existent type declaration
  `MalformedParameterizedTypeException` - if any of the underlying executable's parameter types refer to a parameterized type that cannot be instantiated for any reason

### getParameters

public Parameter[] getParameters()
Returns an array of `Parameter` objects representing all the parameters to the underlying executable represented by this object. An array of length 0 is returned if the executable has no parameters.

The parameters of the underlying executable do not necessarily have unique names, or names that are legal identifiers in the Java programming language (JLS 3.8).

Returns:
  an array of `Parameter` objects representing all the parameters to the underlying executable represented by this object
Throws:
  `MalformedParametersException` - if the class file contains a MethodParameters attribute that is improperly formatted.

### getExceptionTypes

public abstract Class<?>[] getExceptionTypes()
Returns an array of `Class` objects that represent the types of exceptions declared to be thrown by the underlying executable represented by this object. Returns an array of length 0 if the executable declares no exceptions in its `throws` clause.

Returns:
  the exception types declared as being thrown by the executable this object represents

### getGenericExceptionTypes

public Type[] getGenericExceptionTypes()
Returns an array of `Type` objects that represent the exceptions declared to be thrown by this executable object. Returns an array of length 0 if the underlying executable declares no exceptions in its `throws` clause.

If an exception type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

Returns:
  an array of Types that represent the exception types thrown by the underlying executable
Throws:
  `GenericSignatureFormatError` - if the generic method signature does not conform to the format specified in The Java Virtual Machine Specification
  `TypeNotPresentException` - if the underlying executable's `throws` clause refers to a non-existent type declaration
  `MalformedParameterizedTypeException` - if the underlying executable's `throws` clause refers to a parameterized type that cannot be instantiated for any reason

### toGenericString

public abstract String toGenericString()
Returns a string describing this `Executable`, including any type parameters.

Returns:
  a string describing this `Executable`, including any type parameters

### isVarArgs

public boolean isVarArgs()
Returns `true` if this executable was declared to take a variable number of arguments; returns `false` otherwise.

Returns:
  `true` if this executable was declared to take a variable number of arguments; returns `false` otherwise

### isSynthetic

public boolean isSynthetic()
Returns `true` if this executable is a synthetic construct; returns `false` otherwise.

Specified by:
  `isSynthetic` in interface `Member`
Returns:
  true if and only if this executable is a synthetic construct as defined by The Java Language Specification.
See Java Language Specification:
  13.1 The Form of a Binary
See Java Virtual Machine Specification:
  4.6 Methods

### getParameterAnnotations

public abstract Annotation[][] getParameterAnnotations()
Returns an array of arrays of `Annotation`s that represent the annotations on the formal parameters, in declaration order, of the `Executable` represented by this object. Synthetic and mandated parameters (see explanation below), such as the outer "this" parameter to an inner class constructor will be represented in the returned array. If the executable has no parameters (meaning no formal, no synthetic, and no mandated parameters), a zero-length array will be returned. If the `Executable` has one or more parameters, a nested array of length zero is returned for each parameter with no annotations. The annotation objects contained in the returned arrays are serializable. The caller of this method is free to modify the returned arrays; it will have no effect on the arrays returned to other callers. A compiler may add extra parameters that are implicitly declared in source ("mandated"), as well as parameters that are neither implicitly nor explicitly declared in source ("synthetic") to the parameter list for a method. See `Parameter` for more information.

Note that any annotations returned by this method are declaration annotations.

Returns:
  an array of arrays that represent the annotations on the formal and implicit parameters, in declaration order, of the executable represented by this object
See Also:
  - `Parameter`
  - `Parameter.getAnnotations()`

### getAnnotation

public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
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.

Specified by:
  `getAnnotation` in interface `AnnotatedElement`
Overrides:
  `getAnnotation` in class `AccessibleObject`
Type Parameters:
  `T` - the type of the annotation to query for and return if present
Parameters:
  `annotationClass` - the Class object corresponding to the annotation type
Returns:
  this element's annotation for the specified annotation type if present on this element, else null
Throws:
  `NullPointerException` - if the given annotation class is null

### getAnnotationsByType

public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass)
Returns annotations that are associated with this element. If there are no annotations associated with 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.

Specified by:
  `getAnnotationsByType` in interface `AnnotatedElement`
Overrides:
  `getAnnotationsByType` in class `AccessibleObject`
Type Parameters:
  `T` - the type of the annotation to query for and return if present
Parameters:
  `annotationClass` - the Class object corresponding to the annotation type
Returns:
  all this element's annotations for the specified annotation type if associated with this element, else an array of length zero
Throws:
  `NullPointerException` - if the given annotation class is null

### getDeclaredAnnotations

public Annotation[] getDeclaredAnnotations()
Returns annotations that are directly present on this element. This method ignores inherited annotations. If there are no annotations directly present on 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.

Specified by:
  `getDeclaredAnnotations` in interface `AnnotatedElement`
Overrides:
  `getDeclaredAnnotations` in class `AccessibleObject`
Returns:
  annotations directly present on this element

### getAnnotatedReturnType

public abstract AnnotatedType getAnnotatedReturnType()
Returns an `AnnotatedType` object that represents the use of a type to specify the return type of the method/constructor represented by this Executable. If this `Executable` object represents a constructor, the `AnnotatedType` object represents the type of the constructed object. If this `Executable` object represents a method, the `AnnotatedType` object represents the use of a type to specify the return type of the method.

Returns:
  an object representing the return type of the method or constructor represented by this `Executable`

### getAnnotatedReceiverType

public AnnotatedType getAnnotatedReceiverType()
Returns an `AnnotatedType` object that represents the use of a type to specify the receiver type of the method/constructor represented by this `Executable` object. The receiver type of a method/constructor is available only if the method/constructor has a receiver parameter (JLS 8.4.1). If this `Executable` object represents an instance method or represents a constructor of an inner member class, and the method/constructor either has no receiver parameter or has a receiver parameter with no annotations on its type, then the return value is an `AnnotatedType` object representing an element with no annotations. If this `Executable` object represents a static method or represents a constructor of a top level, static member, local, or anonymous class, then the return value is null.

Returns:
  an object representing the receiver type of the method or constructor represented by this `Executable` or `null` if this `Executable` can not have a receiver parameter
See Java Language Specification:
  8.4 Method Declarations
  8.4.1 Formal Parameters
  8.8 Constructor Declarations

### getAnnotatedParameterTypes

public AnnotatedType[] getAnnotatedParameterTypes()
Returns an array of `AnnotatedType` objects that represent the use of types to specify formal parameter types of the method/constructor represented by this Executable. The order of the objects in the array corresponds to the order of the formal parameter types in the declaration of the method/constructor. Returns an array of length 0 if the method/constructor declares no parameters. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones.

Returns:
  an array of objects representing the types of the formal parameters of the method or constructor represented by this `Executable`

### getAnnotatedExceptionTypes

public AnnotatedType[] getAnnotatedExceptionTypes()
Returns an array of `AnnotatedType` objects that represent the use of types to specify the declared exceptions of the method/constructor represented by this Executable. The order of the objects in the array corresponds to the order of the exception types in the declaration of the method/constructor. Returns an array of length 0 if the method/constructor declares no exceptions.

Returns:
  an array of objects representing the declared exceptions of the method or constructor represented by this `Executable`