AnnotatedElement, GenericDeclaration, Member
public final class Method extends Executable
Method provides information about, and access to, a single method on a class or interface. The reflected method may be a class method or an instance method (including an abstract method). A Method permits widening conversions to occur when matching the actual parameters to invoke with the underlying method's formal parameters, but it throws an IllegalArgumentException if a narrowing conversion would occur.
| Modifier and Type | Method | Description | 
|---|---|---|
| boolean | equals | Compares this  Methodagainst the specified object. | 
| AnnotatedType | getAnnotatedReturnType() | Returns an  AnnotatedTypeobject that represents the use of a type to specify the return type of the method/constructor represented by this Executable. | 
| <T extends Annotation> | getAnnotation | Returns this element's annotation for the specified type if such an annotation is present, else null. | 
| Annotation[] | getDeclaredAnnotations() | Returns annotations that are directly present on this element. | 
| Class | getDeclaringClass() | Returns the  Classobject representing the class or interface that declares the method represented by this object. | 
| Object | getDefaultValue() | Returns the default value for the annotation member represented by this  Methodinstance. | 
| Class<?>[] | getExceptionTypes() | Returns an array of  Classobjects that represent the types of exceptions declared to be thrown by the underlying executable represented by this object. | 
| Type[] | getGenericExceptionTypes() | Returns an array of  Typeobjects that represent the exceptions declared to be thrown by this executable object. | 
| Type[] | getGenericParameterTypes() | Returns an array of  Typeobjects that represent the formal parameter types, in declaration order, of the executable represented by this object. | 
| Type | getGenericReturnType() | Returns a  Typeobject that represents the formal return type of the method represented by thisMethodobject. | 
| int | getModifiers() | Returns the Java language modifiers for the executable represented by this object. | 
| String | getName() | Returns the name of the method represented by this  Methodobject, as aString. | 
| Annotation[][] | getParameterAnnotations() | Returns an array of arrays of  Annotations that represent the annotations on the formal parameters, in declaration order, of theExecutablerepresented by this object. | 
| int | getParameterCount() | Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object. | 
| Class<?>[] | getParameterTypes() | Returns an array of  Classobjects that represent the formal parameter types, in declaration order, of the executable represented by this object. | 
| Class | getReturnType() | Returns a  Classobject that represents the formal return type of the method represented by thisMethodobject. | 
| TypeVariable<Method>[] | getTypeParameters() | Returns an array of  TypeVariableobjects that represent the type variables declared by the generic declaration represented by thisGenericDeclarationobject, in declaration order. | 
| int | hashCode() | Returns a hashcode for this  Method. | 
| Object | invoke | Invokes the underlying method represented by this  Methodobject, on the specified object with the specified parameters. | 
| boolean | isBridge() | Returns  trueif this method is a bridge method; returnsfalseotherwise. | 
| boolean | isDefault() | Returns  trueif this method is a default method; returnsfalseotherwise. | 
| boolean | isSynthetic() | Returns  trueif this executable is a synthetic construct; returnsfalseotherwise. | 
| boolean | isVarArgs() | Returns  trueif this executable was declared to take a variable number of arguments; returnsfalseotherwise. | 
| void | setAccessible | Set the  accessibleflag for this reflected object to the indicated boolean value. | 
| String | toGenericString() | Returns a string describing this  Method, including type parameters. | 
| String | toString() | Returns a string describing this  Method. | 
accessFlags, getAnnotatedExceptionTypes, getAnnotatedParameterTypes, getAnnotatedReceiverType, getAnnotationsByType, getParameters
canAccess, getAnnotations, getDeclaredAnnotation, getDeclaredAnnotationsByType, isAccessible, isAnnotationPresent, setAccessible, trySetAccessible
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
getAnnotations, getDeclaredAnnotation, getDeclaredAnnotationsByType, isAnnotationPresent
public void setAccessible(boolean flag)
AccessibleObjectaccessible flag for this reflected object to the indicated boolean value. A value of true indicates that the reflected object should suppress checks for Java language access control when it is used. A value of false indicates that the reflected object should enforce checks for Java language access control when it is used, with the variation noted in the class description.  This method may be used by a caller in class C to enable access to a member of declaring class D if any of the following hold: 
C and D are in the same module. public and D is public in a package that the module containing D exports to at least the module containing C. protected static, D is public in a package that the module containing D exports to at least the module containing C, and C is a subclass of D. D is in a package that the module containing D opens to at least the module containing C. All packages in unnamed and open modules are open to all modules and so this method always succeeds when D is in an unnamed or open module.  This method may be used by JNI code with no caller class on the stack to enable access to a member of declaring class D if and only if: 
public and D is public in a package that the module containing D exports unconditionally. This method cannot be used to enable access to private members, members with default (package) access, protected instance members, or protected constructors when the declaring class is in a different module to the caller and the package containing the declaring class is not open to the caller's module.
This method cannot be used to enable write access to a non-modifiable final field. The following fields are non-modifiable:
 The accessible flag when true suppresses Java language access control checks to only enable read access to these non-modifiable final fields. 
 If there is a security manager, its checkPermission method is first called with a ReflectPermission("suppressAccessChecks") permission.
setAccessible in class AccessibleObject
flag - the new value for the accessible flagInaccessibleObjectException - if access cannot be enabledSecurityException - if the request is denied by the security managerpublic Class<?> getDeclaringClass()
Class object representing the class or interface that declares the method represented by this object.getDeclaringClass in interface Member
getDeclaringClass in class Executable
public String getName()
Method object, as a String.getName in interface Member
getName in class Executable
public int getModifiers()
getModifiers in interface Member
getModifiers in class Executable
public TypeVariable<Method>[] getTypeParameters()
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
getTypeParameters in class Executable
TypeVariable objects that represent the type variables declared by this generic declarationGenericSignatureFormatError - if the generic signature of this generic declaration does not conform to the format specified in The Java Virtual Machine Specification
public Class<?> getReturnType()
Class object that represents the formal return type of the method represented by this Method object.public Type getGenericReturnType()
Type object that represents the formal return type of the method represented by this Method object. If the return type is a parameterized type, the Type object returned must accurately reflect the actual type arguments used in the source code. 
If the return type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.
Type object that represents the formal return type of the underlying methodGenericSignatureFormatError - if the generic method signature does not conform to the format specified in The Java Virtual Machine Specification
TypeNotPresentException - if the underlying method's return type refers to a non-existent class or interface declarationMalformedParameterizedTypeException - if the underlying method's return type refers to a parameterized type that cannot be instantiated for any reasonpublic Class<?>[] getParameterTypes()
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.getParameterTypes in class Executable
public int getParameterCount()
getParameterCount in class Executable
public Type[] getGenericParameterTypes()
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.
getGenericParameterTypes in class Executable
Types that represent the formal parameter types of the underlying executable, in declaration orderGenericSignatureFormatError - 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 declarationMalformedParameterizedTypeException - if any of the underlying executable's parameter types refer to a parameterized type that cannot be instantiated for any reasonpublic Class<?>[] getExceptionTypes()
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.getExceptionTypes in class Executable
public Type[] getGenericExceptionTypes()
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.
getGenericExceptionTypes in class Executable
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 declarationMalformedParameterizedTypeException - if the underlying executable's throws clause refers to a parameterized type that cannot be instantiated for any reasonpublic boolean equals(Object obj)
Method against the specified object. Returns true if the objects are the same. Two Methods are the same if they were declared by the same class and have the same name and formal parameter types and return type.public int hashCode()
Method. The hashcode is computed as the exclusive-or of the hashcodes for the underlying method's declaring class name and the method's name.public String toString()
Method. The string is formatted as the method access modifiers, if any, followed by the method return type, followed by a space, followed by the class declaring the method, followed by a period, followed by the method name, followed by a parenthesized, comma-separated list of the method's formal parameter types. If the method throws checked exceptions, the parameter list is followed by a space, followed by the word "throws" followed by a comma-separated list of the thrown exception types. For example: 
    public boolean java.lang.Object.equals(java.lang.Object)
  The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is public, protected or private first, and then other modifiers in the following order: abstract, default, static, final, synchronized, native, strictfp.
toString in class Object
Method
public String toGenericString()
Method, including type parameters. The string is formatted as the method access modifiers, if any, followed by an angle-bracketed comma-separated list of the method's type parameters, if any, including informative bounds of the type parameters, if any, followed by the method's generic return type, followed by a space, followed by the class declaring the method, followed by a period, followed by the method name, followed by a parenthesized, comma-separated list of the method's generic formal parameter types. If this method was declared to take a variable number of arguments, instead of denoting the last parameter as "Type[]", it is denoted as "Type...". A space is used to separate access modifiers from one another and from the type parameters or return type. If there are no type parameters, the type parameter list is elided; if the type parameter list is present, a space separates the list from the class name. If the method is declared to throw exceptions, the parameter list is followed by a space, followed by the word "throws" followed by a comma-separated list of the generic thrown exception types. The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is public, protected or private first, and then other modifiers in the following order: abstract, default, static, final, synchronized, native, strictfp.
toGenericString in class Executable
Method, include type parameterspublic Object invoke(Object obj, Object... args) throws IllegalAccessException, InvocationTargetException
Method object, on the specified object with the specified parameters. Individual parameters are automatically unwrapped to match primitive formal parameters, and both primitive and reference parameters are subject to method invocation conversions as necessary. If the underlying method is static, then the specified obj argument is ignored. It may be null. 
If the number of formal parameters required by the underlying method is 0, the supplied args array may be of length 0 or null. 
If the underlying method is an instance method, it is invoked using dynamic method lookup as documented in The Java Language Specification, section 15.12.4.4; in particular, overriding based on the runtime type of the target object may occur.
If the underlying method is static, the class that declared the method is initialized if it has not already been initialized.
If the method completes normally, the value it returns is returned to the caller of invoke; if the value has a primitive type, it is first appropriately wrapped in an object. However, if the value has the type of an array of a primitive type, the elements of the array are not wrapped in objects; in other words, an array of primitive type is returned. If the underlying method return type is void, the invocation returns null.
obj - the object the underlying method is invoked fromargs - the arguments used for the method callobj with parameters args
IllegalAccessException - if this Method object is enforcing Java language access control and the underlying method is inaccessible.IllegalArgumentException - if the method is an instance method and the specified object argument is not an instance of the class or interface declaring the underlying method (or of a subclass or implementor thereof); if the number of actual and formal parameters differ; if an unwrapping conversion for primitive arguments fails; or if, after possible unwrapping, a parameter value cannot be converted to the corresponding formal parameter type by a method invocation conversion.InvocationTargetException - if the underlying method throws an exception.NullPointerException - if the specified object is null and the method is an instance method.ExceptionInInitializerError - if the initialization provoked by this method fails.public boolean isBridge()
true if this method is a bridge method; returns false otherwise.One example use of bridge methods is as a technique for a Java compiler to support covariant overrides, where a subclass overrides a method and gives the new method a more specific return type than the method in the superclass. While the Java language specification forbids a class declaring two methods with the same parameter types but a different return type, the virtual machine does not. A common case where covariant overrides are used is for a Cloneable class where the clone method inherited from 
 java.lang.Object is overridden and declared to return the type of the class. For example, Object declares 
protected Object clone() throws CloneNotSupportedException {...}EnumSet<E> declares its language-level covariant override public EnumSet<E> clone() {...}EnumSet would have two clone methods, one returning EnumSet<E> and the second a bridge method returning Object. The bridge method is a JVM-level override of Object.clone(). The body of the 
 clone bridge method calls its non-bridge counterpart and returns its result.true if this method is a bridge method; returns false otherwisepublic boolean isVarArgs()
true if this executable was declared to take a variable number of arguments; returns false otherwise.isVarArgs in class Executable
true if this executable was declared to take a variable number of arguments; returns false otherwisepublic boolean isSynthetic()
true if this executable is a synthetic construct; returns false otherwise.isSynthetic in interface Member
isSynthetic in class Executable
public boolean isDefault()
true if this method is a default method; returns false otherwise. A default method is a public non-abstract instance method, that is, a non-static method with a body, declared in an interface.public Object getDefaultValue()
Method instance. If the member is of a primitive type, an instance of the corresponding wrapper type is returned. Returns null if no default is associated with the member, or if the method instance does not represent a declared member of an annotation type.Method instance.TypeNotPresentException - if the annotation is of type Class and no definition can be found for the default class value.public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
Note that any annotation returned by this method is a declaration annotation.
getAnnotation in interface AnnotatedElement
getAnnotation in class Executable
T - the type of the annotation to query for and return if presentannotationClass - the Class object corresponding to the annotation typeNullPointerException - if the given annotation class is nullpublic Annotation[] getDeclaredAnnotations()
Note that any annotations returned by this method are declaration annotations.
getDeclaredAnnotations in interface AnnotatedElement
getDeclaredAnnotations in class AccessibleObject
public Annotation[][] getParameterAnnotations()
Annotations 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.
getParameterAnnotations in class Executable
public AnnotatedType getAnnotatedReturnType()
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.getAnnotatedReturnType in class Executable
Executable
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