Class Constructor<T>

public void setAccessible(boolean flag)

Set the accessible 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.
• 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.

This method cannot be used to enable write access to a non-modifiable final field. The following fields are non-modifiable:

• 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.

A SecurityException is also thrown if this object is a Constructor object for the class Class and flag is true.

public Class<T> getDeclaringClass()

Returns the Class object representing the class that declares the constructor represented by this object.

public String getName()

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

public int getModifiers()

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

public 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.

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. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones.

public int getParameterCount()

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

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. 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.

public 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.

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.

public 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.

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.

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.HashMap(int,float)
 

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.

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, including informative bounds of the 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 class name. 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 generic 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.

public 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.

public boolean isVarArgs()

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

public boolean isSynthetic()

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

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.

Note that any annotation returned by this method is a declaration annotation.

public 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.

Note that any annotations returned by this method are declaration annotations.

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.

Note that any annotations returned by this method are declaration annotations.

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.

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 an instance method or represents a constructor of an inner member class, and the method/constructor either has no 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 or represents a constructor of a top level, static member, local, or anonymous class, then the return value is null.