T - the class in which the constructor is declaredpublic final class Constructor<T> extends Executable
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.
Member, Class, Class.getConstructors(), Class.getConstructor(Class[]), Class.getDeclaredConstructors()
DECLARED, PUBLIC public Class<T> 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 this constructor, as a string. This is the binary name of the constructor's declaring class.
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<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. 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<?>[] 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 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.
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 Constructor. The hashcode is the same as the hashcode for the underlying constructor's declaring class name.
hashCode in class Object
Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)
public String toString()
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.
public String toGenericString()
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.
toGenericString in class Executable
Constructor, include type parameterspublic T newInstance(Object... initargs)
throws InstantiationException,
IllegalAccessException,
IllegalArgumentException,
InvocationTargetException 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.
initargs - 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)IllegalAccessException - if this Constructor object is enforcing Java language access control and the underlying constructor is inaccessible.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.InstantiationException - if the class that declares the underlying constructor represents an abstract class.InvocationTargetException - if the underlying constructor throws an exception.ExceptionInInitializerError - if the initialization provoked by this method fails.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 <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
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 a constructor or instance method that does not have a 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, then the return value is null.
getAnnotatedReceiverType in class Executable
Executable
© 1993–2017, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.