Java method class type

Class Method

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.

Field Summary

Fields declared in interface java.lang.reflect.Member

Method Summary

Returns an AnnotatedType object that represents the use of a type to specify the return type of the method/constructor represented by this Executable.

Returns this element’s annotation for the specified type if such an annotation is present, else null.

Returns the Class object representing the class or interface that declares the method represented by this object.

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 Type objects that represent the exceptions declared to be thrown by this executable object.

Returns an array of Type objects that represent the formal parameter types, in declaration order, of the executable represented by this object.

Returns a Type object that represents the formal return type of the method represented by this Method object.

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.

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

Returns an array of Class objects that represent the formal parameter types, in declaration order, of the executable represented by this object.

Returns a Class object that represents the formal return type of the method represented by this Method object.

Returns an array of TypeVariable objects that represent the type variables declared by the generic declaration represented by this GenericDeclaration object, in declaration order.

Invokes the underlying method represented by this Method object, on the specified object with the specified parameters.

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

Methods declared in class java.lang.reflect.Executable

Methods declared in class java.lang.reflect.AccessibleObject

Methods declared in class java.lang.Object

Methods declared in interface java.lang.reflect.AnnotatedElement

Method Details

setAccessible

• C and D are in the same module.
• The member is public and D is public in a package that the module containing D exports to at least the module containing C .
• The member is 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 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.

• static final fields declared in any class or interface
• final fields declared in a hidden class
• final fields declared in a record

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.

getDeclaringClass

Returns the Class object representing the class or interface that declares the method represented by this object.

getName

getModifiers

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.

getReturnType

Returns a Class object that represents the formal return type of the method represented by this Method object.

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 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.

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.

getParameterCount

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

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.

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.

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.

equals

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.

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.

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 .

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, 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 .

invoke

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, 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.

isBridge

API Note: A bridge method is a synthetic method created by a Java compiler alongside a method originating from the source code. Bridge methods are used by Java compilers in various circumstances to span differences in Java programming language semantics and JVM semantics. 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

isVarArgs

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

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