public final class Method extends Executable
A 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.
Member, Class, Class.getMethods(), Class.getMethod(String, Class[]), Class.getDeclaredMethods(), Class.getDeclaredMethod(String, Class[])
DECLARED, PUBLIC public Class<?> getDeclaringClass()
Returns the Class object representing the class or interface that declares the executable represented by this object.
getDeclaringClass in interface Member
getDeclaringClass in class Executable
public String getName()
Returns the name of the method represented by this Method object, as a String.
getName in interface Member
getName in class Executable
public int getModifiers()
Returns the Java language modifiers for the executable represented by this object.
getModifiers in interface Member
getModifiers in class Executable
Modifierpublic TypeVariable<Method>[] 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.
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()
Returns a Class object that represents the formal return type of the method represented by this Method object.
public Type getGenericReturnType()
Returns a 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 parameters 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 type declarationMalformedParameterizedTypeException - if the underlying method's return typed refers to a parameterized type that cannot be instantiated for any reasonpublic 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.
getParameterTypes in class Executable
public int getParameterCount()
Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object.
getParameterCount in class Executable
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. Returns an array of length 0 if the underlying executable takes no parameters.
If a formal parameter type is a parameterized type, the Type object returned for it must accurately reflect the actual type parameters 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()
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.
getExceptionTypes in class Executable
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.
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)
Compares this 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.
equals in class Object
obj - the reference object with which to compare.true if this object is the same as the obj argument; false otherwise.Object.hashCode(), HashMap
public int hashCode()
Returns a hashcode for this 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.
hashCode in class Object
Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)
public String toString()
Returns a string describing this 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.
public String toGenericString()
Returns a string describing this 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, 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,
IllegalArgumentException,
InvocationTargetException Invokes the underlying method represented by this 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, Second Edition, section 15.12.4.4; in particular, overriding based on the runtime type of the target object will 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()
Returns true if this method is a bridge method; returns false otherwise.
public boolean isVarArgs()
Returns true if this executable was declared to take a variable number of arguments; returns false otherwise.
isVarArgs in class Executable
true if an only if this executable was declared to take a variable number of arguments.public boolean isSynthetic()
Returns true if this executable is a synthetic construct; returns false otherwise.
isSynthetic in interface Member
isSynthetic in class Executable
public boolean isDefault()
Returns 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 type.
public Object getDefaultValue()
Returns the default value for the annotation member represented by this 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)
Returns this element's annotation for the specified type if such an annotation is present, else null.
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()
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.
getDeclaredAnnotations in interface AnnotatedElement
getDeclaredAnnotations in class Executable
public Annotation[][] getParameterAnnotations()
Returns an array of arrays of 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.
getParameterAnnotations in class Executable
Parameter, Parameter.getAnnotations()
public 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.
getAnnotatedReturnType in class Executable
Executable
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