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Java Fundamental Classes Reference

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The java.lang.reflect Package
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Constructor

Name

Constructor

Synopsis

Class Name:

java.lang.reflect.Constructor

Superclass:

java.lang.Object

Immediate Subclasses:

None

Interfaces Implemented:

java.lang.reflect.Member

Availability:

New as of JDK 1.1

Description

The Constructor class represents a constructor of a class. A Constructor object can be obtained by calling the getConstructor() method of a Class object. Constructor provides methods for getting the name, modifiers, parameters, exceptions, and declaring class of a constructor. The newInstance() method can create a new instance of the class that declares a constructor.

Class Summary

public final class java.lang.reflect.Constructor extends java.lang.Object
                   implements java.lang.reflect.Member {
  // Instance Methods
  public boolean equals(Object obj); 
  public Class getDeclaringClass();
  public Class[] getExceptionTypes();
  public native int getModifiers();
  public String getName();
  public Class[] getParameterTypes();
  public int hashCode();
  public native Object newInstance(Object[] initargs);
  public String toString();
}

Instance Methods

equals

public boolean equals(Object obj)

Parameters

obj

The object to be compared with this object.

Returns

true if the objects are equal; false if they are not.

Overrides

Object.equals()

Description

This method returns true if obj is an instance of Constructor, and it is equivalent to this Constructor.

getDeclaringClass

public Class getDeclaringClass()

Returns

The Class object that represents the class that declared this constructor.

Implements

Member.getDeclaringClass()

Description

This method returns the Class object for the class in which this constructor is declared.

getExceptionTypes

public Class[] getExceptionTypes()

Returns

An array that contains the Class objects that describe the exceptions that can be thrown by this constructor.

Description

This method returns an array of Class objects that represents the throws clause of this constructor. If the constructor does not throw any exceptions, an array of length 0 is returned. As of Java 1.1.2, this method is not properly supported: it always returns an empty array.

getModifiers

public native int getModifiers()

Returns

An integer that represents the modifier keywords used to declare this constructor.

Implements

Member.getModifiers()

Description

This method returns an integer value that represents the modifiers of this constructor. The Modifier class should decode the returned value.

getName

public String getName()

Returns

The name of this constructor as a String.

Implements

Member.getName()

Description

This method returns the name of this constructor, which is always the same as the name of the declaring class.

getParameterTypes

public Class[] getParameterTypes()

Returns

An array that contains the Class objects that describe the parameter types that this constructor accepts.

Description

This method returns an array of Class objects that represents the parameter types this constructor accepts. The parameter types are listed in the order in which they are declared. If the constructor does not take any parameters, an array of length 0 is returned.

hashCode

public int hashCode()

Returns

A hashcode for this object.

Overrides

Object.hashCode()

Description

This method returns a hashcode for this Constructor.

newInstance

 public native Object newInstance(Object[] initargs) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException 

Parameters

initargs

An array of arguments to be passed to this constructor.

Returns

The newly created object.

Throws

InstantiationException

If the declaring class of this constructor is abstract.

IllegalAccessException

If the constructor is inaccessible.

IllegalArgumentException

If initargs is the wrong length or contains any value of the wrong type.

InvocationTargetException

If the constructor itself throws an exception.

Description

This method executes the constructor represented by this object using the given array of arguments. Thus, it creates and initializes a new instance of the declaring class of the constructor. If a particular parameter is of a primitive type, the corresponding argument is automatically unwrapped and converted to the appropriate type, if possible. If that is not possible, an IllegalArgumentException is thrown. If the constructor itself throws an exception, the exception is placed in an InvocationTargetException, which is then thrown to the caller of newInstance(). If the constructor completes normally, the newly created instance is returned.

toString

public String toString()

Returns

A string representation of this object.

Overrides

Object.toString()

Description

This method returns a string representation of this Constructor. This string contains the access modifiers of the constructor, if any, followed by the fully qualified name of the declaring class and a list of the parameters of the constructor, if any. The list is enclosed by parentheses, and the individual parameters are separated by commas. If the constructor does not have any parameters, just the parentheses are included in the string.

Inherited Methods

Method

Inherited From

Method

Inherited From

clone()

Object

finalize()

Object

getClass()

Object

notify()

Object

notifyAll()

Object

wait()

Object

wait(long)

Object

wait(long, int)

Object

See Also

Class, Field, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, Member, Method, Modifier, Object


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