Added in API level 1

Constructor

class Constructor<T : Any!> : Executable

kotlin.Any
↳	java.lang.reflect.AccessibleObject
	↳	java.lang.reflect.Executable
		↳	java.lang.reflect.Constructor

Constructor provides information about, and access to, a single constructor for a class.

Constructor permits widening conversions to occur when matching the actual parameters to newInstance() with the underlying constructor's formal parameters, but throws an IllegalArgumentException if a narrowing conversion would occur.

Summary

Inherited constants
From class Member Int DECLARED Identifies the set of declared members of a class or interface. Inherited members are not included. Int PUBLIC Identifies the set of all public members of a class or interface, including inherited members.

Public methods
Boolean	equals(other: Any?) Compares this Constructor against the specified object.
T?	getAnnotation(annotationClass: Class<T>) Returns this element's annotation for the specified type if such an annotation is present, else null.
Array<Annotation!>	getDeclaredAnnotations() Returns annotations that are directly present on this element.
Class<T>	getDeclaringClass() Returns the Class object representing the class or interface that declares the executable represented by this object.
Array<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.
Array<Type!>	getGenericExceptionTypes() Returns an array of Type objects that represent the exceptions declared to be thrown by this executable object.
Array<Type!>	getGenericParameterTypes() Returns an array of Type objects that represent the formal parameter types, in declaration order, of the executable represented by this object.
Int	getModifiers() Returns the Java language modifiers for the executable represented by this object.
String	getName() Returns the name of this constructor, as a string.
Array<Array<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.
Int	getParameterCount() Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object.
Array<Class<*>!>	getParameterTypes() Returns an array of Class objects that represent the formal parameter types, in declaration order, of the executable represented by this object.
Array<TypeVariable<Constructor<T>!>!>	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.
Int	hashCode() Returns a hashcode for this Constructor.
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.
T	newInstance(vararg initargs: Any!) Uses the constructor represented by this Constructor object to create and initialize a new instance of the constructor's declaring class, with the specified initialization parameters.
String	toGenericString() Returns a string describing this Constructor, including type parameters.
String	toString() Returns a string describing this Constructor.

Inherited functions
From class AccessibleObject Array<Annotation!> getAnnotations() T? getDeclaredAnnotation(annotationClass: Class<T>) Array<T>! getDeclaredAnnotationsByType(annotationClass: Class<T>) Boolean isAccessible() Get the value of the accessible flag for this object. Unit setAccessible(flag: Boolean) Set the accessible flag for this object to the indicated boolean value. A value of true indicates that the reflected object should suppress Java language access checking when it is used. A value of false indicates that the reflected object should enforce Java language access checks. First, if there is a security manager, its checkPermission method is called with a ReflectPermission("suppressAccessChecks") permission. A SecurityException is raised if flag is true but accessibility of this object may not be changed (for example, if this element object is a Constructor object for the class java.lang.Class). A SecurityException is raised if this object is a object for the class java.lang.Class, and flag is true. Unit setAccessible(array: Array<AccessibleObject!>!, flag: Boolean) Convenience method to set the accessible flag for an array of objects with a single security check (for efficiency). First, if there is a security manager, its checkPermission method is called with a ReflectPermission("suppressAccessChecks") permission. A SecurityException is raised if flag is true but accessibility of any of the elements of the input array may not be changed (for example, if the element object is a Constructor object for the class ). In the event of such a SecurityException, the accessibility of objects is set to flag for array elements upto (and excluding) the element for which the exception occurred; the accessibility of elements beyond (and including) the element for which the exception occurred is unchanged.
From class Executable Array<T>! getAnnotationsByType(annotationClass: Class<T>) 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 getAnnotation(java.lang.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. Array<Parameter!> getParameters() Returns an array of Parameter objects that represent all the parameters to the underlying executable represented by this object. Returns an array of length 0 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). Boolean isAnnotationPresent(annotationType: Class<out Annotation!>)

Public methods

equals

Added in API level 1

fun equals(other: Any?): Boolean

Compares this Constructor against the specified object. Returns true if the objects are the same. Two Constructor objects are the same if they were declared by the same class and have the same formal parameter types.

Parameters
obj	the reference object with which to compare.

Return
Boolean	true if this object is the same as the obj argument; false otherwise.

getAnnotation

Added in API level 1

fun <T : Annotation!> getAnnotation(annotationClass: Class<T>): T?

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

Parameters
<T>	the type of the annotation to query for and return if present
annotationClass	Class<T>: the Class object corresponding to the annotation type

Return
T?	this element's annotation for the specified annotation type if present on this element, else null

Exceptions
java.lang.NullPointerException	if the given annotation class is null

getDeclaredAnnotations

Added in API level 1

fun getDeclaredAnnotations(): Array<Annotation!>

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.

Return
Array<Annotation!>	annotations directly present on this element

getDeclaringClass

Added in API level 1

fun getDeclaringClass(): Class<T>

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

Return
Class<T>	an object representing the declaring class of the underlying member

getExceptionTypes

Added in API level 1

fun getExceptionTypes(): Array<Class<*>!>

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.

Return
Array<Class<*>!>	the exception types declared as being thrown by the executable this object represents

getGenericExceptionTypes

Added in API level 1

fun getGenericExceptionTypes(): Array<Type!>

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.

Return
Array<Type!>	an array of Types that represent the exception types thrown by the underlying executable

Exceptions
java.lang.reflect.GenericSignatureFormatError	if the generic method signature does not conform to the format specified in The Java™ Virtual Machine Specification
java.lang.TypeNotPresentException	if the underlying executable's throws clause refers to a non-existent type declaration
java.lang.reflect.MalformedParameterizedTypeException	if the underlying executable's throws clause refers to a parameterized type that cannot be instantiated for any reason

getGenericParameterTypes

Added in API level 1

fun getGenericParameterTypes(): Array<Type!>

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.

Return
Array<Type!>	an array of Types that represent the formal parameter types of the underlying executable, in declaration order

Exceptions
java.lang.reflect.GenericSignatureFormatError	if the generic method signature does not conform to the format specified in The Java™ Virtual Machine Specification
java.lang.TypeNotPresentException	if any of the parameter types of the underlying executable refers to a non-existent type declaration
java.lang.reflect.MalformedParameterizedTypeException	if any of the underlying executable's parameter types refer to a parameterized type that cannot be instantiated for any reason

getModifiers

Added in API level 1

fun getModifiers(): Int

Returns the Java language modifiers for the executable represented by this object.

Return
Int	the Java language modifiers for the underlying member

getName

Added in API level 1

fun getName(): String

Returns the name of this constructor, as a string. This is the binary name of the constructor's declaring class.

Return
String	the simple name of the underlying member

getParameterAnnotations

Added in API level 1

fun getParameterAnnotations(): Array<Array<Annotation!>!>

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 for more information.

Return
Array<Array<Annotation!>!>	an array of arrays that represent the annotations on the formal and implicit parameters, in declaration order, of the executable represented by this object

getParameterCount

Added in API level 26

fun getParameterCount(): Int

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

Return
Int	The number of formal parameters for the executable this object represents

getParameterTypes

Added in API level 1

fun getParameterTypes(): Array<Class<*>!>

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.

Return
Array<Class<*>!>	the parameter types for the executable this object represents

getTypeParameters

Added in API level 1

fun getTypeParameters(): Array<TypeVariable<Constructor<T>!>!>

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.

Return
Array<TypeVariable<Constructor<T>!>!>	an array of TypeVariable objects that represent the type variables declared by this generic declaration

Exceptions
java.lang.reflect.GenericSignatureFormatError	if the generic signature of this generic declaration does not conform to the format specified in The Java™ Virtual Machine Specification

hashCode

Added in API level 1

fun hashCode(): Int

Returns a hashcode for this Constructor. The hashcode is the same as the hashcode for the underlying constructor's declaring class name.

Return
Int	a hash code value for this object.

isSynthetic

Added in API level 1

fun isSynthetic(): Boolean

Returns true if this executable is a synthetic construct; returns false otherwise.

Return
Boolean	true if and only if this executable is a synthetic construct as defined by The Java™ Language Specification.

isVarArgs

Added in API level 1

fun isVarArgs(): Boolean

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

Return
Boolean	true if an only if this executable was declared to take a variable number of arguments.

newInstance

Added in API level 1

fun newInstance(vararg initargs: Any!): T

Uses the constructor represented by this Constructor object to create and initialize a new instance of the constructor's declaring class, with the specified initialization 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 number of formal parameters required by the underlying constructor is 0, the supplied initargs array may be of length 0 or null.

If the constructor's declaring class is an inner class in a non-static context, the first argument to the constructor needs to be the enclosing instance; see section 15.9.3 of The Java™ Language Specification.

If the required access and argument checks succeed and the instantiation will proceed, the constructor's declaring class is initialized if it has not already been initialized.

If the constructor completes normally, returns the newly created and initialized instance.

Parameters
initargs	Any!: array of objects to be passed as arguments to the constructor call; values of primitive types are wrapped in a wrapper object of the appropriate type (e.g. a float in a Float)

Return
T	a new object created by calling the constructor this object represents

Exceptions
java.lang.IllegalAccessException	if this Constructor object is enforcing Java language access control and the underlying constructor is inaccessible.
java.lang.IllegalArgumentException	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; if this constructor pertains to an enum type.
java.lang.InstantiationException	if the class that declares the underlying constructor represents an abstract class.
java.lang.reflect.InvocationTargetException	if the underlying constructor throws an exception.
java.lang.ExceptionInInitializerError	if the initialization provoked by this method fails.

toGenericString

Added in API level 1

fun toGenericString(): String

Returns a string describing this Constructor, including type parameters. The string is formatted as the constructor access modifiers, if any, followed by an angle-bracketed comma separated list of the constructor's type parameters, if any, followed by the fully-qualified name of the declaring class, followed by a parenthesized, comma-separated list of the constructor's generic formal parameter types. If this constructor 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 constructor 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 thrown exception types.

The only possible modifiers for constructors are the access modifiers public, protected or private. Only one of these may appear, or none if the constructor has default (package) access.

Return
String	a string describing this Constructor, include type parameters

toString

Added in API level 1

fun toString(): String

Returns a string describing this Constructor. The string is formatted as the constructor access modifiers, if any, followed by the fully-qualified name of the declaring class, followed by a parenthesized, comma-separated list of the constructor's formal parameter types. For example:

public java.util.Hashtable(int,float)
  

The only possible modifiers for constructors are the access modifiers public, protected or private. Only one of these may appear, or none if the constructor has default (package) access.

Return
String	a string describing this Constructor