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Java Fundamental Classes Reference

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The java.lang.reflect Package
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Method

Name

Method

Synopsis

Class Name:

java.lang.reflect.Method

Superclass:

java.lang.Object

Immediate Subclasses:

None

Interfaces Implemented:

java.lang.reflect.Member

Availability:

New as of JDK 1.1

Description

The Method class represents a method of a class. A Method object can be obtained by calling the getMethod() method of a Class object. Method provides methods for getting the name, modifiers, return type, parameters, exceptions, and declaring class of a method. The invoke() method can be used to run the method.

Class Summary


public final class java.lang.reflect.Method 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 Class getReturnType();
  public int hashCode();
  public native Object invoke(Object obj, Object[] args);
  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 Method, and it is equivalent to this Method.

getDeclaringClass

public Class getDeclaringClass()

Returns

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

Implements

Member.getDeclaringClass()

Description

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

getExceptionTypes

public Class[] getExceptionTypes()

Returns

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

Description

This method returns an array of Class objects that represents the throws clause of this method. If the method 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 method.

Implements

Member.getModifiers()

Description

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

getName

public String getName()

Returns

The name of this method as a String.

Implements

Member.getName()

Description

This method returns the name of this method.

getParameterTypes

public Class[] getParameterTypes()

Returns

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

Description

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

getReturnType

public Class getReturnType()

Returns

The Class object that represents the return type of this method.

Description

This method returns the Class object for the type that this method returns.

hashCode

public int hashCode()

Returns

A hashcode for this object.

Overrides

Object.hashCode()

Description

This method returns a hashcode for this Method.

invoke

 public native Object invoke(Object obj, Object[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException 

Parameters

obj

The instance upon which this method is invoked.

args

An array of arguments to be passed to this method.

Returns

A Object that contains the return value of the invoked method.

Throws

IllegalAccessException

If the method is inaccessible.

IllegalArgumentException

If obj is not the correct type, or if args is the wrong length or contains the wrong types.

InvocationTargetException

If the method itself throws an exception.

NullPointerException

If obj is null.

Description

This method executes the method represented by this object on the given object using the given array of arguments. If the method is declared static, the obj parameter is ignored. Otherwise, the object supplied must be an instance of the class that declares this method.

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 method itself throws an exception, the exception is placed in an InvocationTargetException, which is then thrown to the caller of invoke().

If the method completes normally, the value it returns is returned. If the value is of a primitive type, the value is wrapped in an appropriate object and the object is returned. If the return type is void, null 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 Method. This string contains the access modifiers of the method, if any, followed by the return type, the fully qualified name of the declaring class, a period, the name of the method, and a list of the parameters of the method, if any. The list is enclosed by parentheses and the individual parameters are separated by commas. If the method 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, Constructor, Field, IllegalAccessException, IllegalArgumentException, InvocationTargetException, Member, Modifier, NullPointerException, Object


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