ObjectStreamClass

public class ObjectStreamClass extends Object
implements Serializable

Serialization's descriptor for classes. It contains the name and serialVersionUID of the class. The ObjectStreamClass for a specific class loaded in this Java VM can be found/created using the lookup method.

The algorithm to compute the SerialVersionUID is described in Object Serialization Specification, Section 4.6, Stream Unique Identifiers.

See Also

• ObjectStreamField
• Object Serialization Specification, Section 4, Class Descriptors

Field Summary

public static final ObjectStreamField[]

NO_FIELDS

serialPersistentFields value indicating no serializable fields

Public Method Summary

Class<?>	forClass() Return the class in the local VM that this version is mapped to.
ObjectStreamField	getField(String name) Get the field of this class by name.
ObjectStreamField[]	getFields() Return an array of the fields of this serializable class.
String	getName() Returns the name of the class described by this descriptor.
long	getSerialVersionUID() Return the serialVersionUID for this class.
static ObjectStreamClass	lookup(Class<?> cl) Find the descriptor for a class that can be serialized.
static ObjectStreamClass	lookupAny(Class<?> cl) Returns the descriptor for any class, regardless of whether it implements Serializable.
String	toString() Return a string describing this ObjectStreamClass.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Fields

public static final ObjectStreamField[] NO_FIELDS

serialPersistentFields value indicating no serializable fields

Public Methods

public Class<?> forClass ()

Return the class in the local VM that this version is mapped to. Null is returned if there is no corresponding local class.

Returns

• the Class instance that this descriptor represents

public ObjectStreamField getField (String name)

Get the field of this class by name.

Parameters

name	the name of the data field to look for

Returns

• The ObjectStreamField object of the named field or null if there is no such named field.

public ObjectStreamField[] getFields ()

Return an array of the fields of this serializable class.

Returns

• an array containing an element for each persistent field of this class. Returns an array of length zero if there are no fields.

public String getName ()

Returns the name of the class described by this descriptor. This method returns the name of the class in the format that is used by the Class.getName() method.

Returns

• a string representing the name of the class

public long getSerialVersionUID ()

Return the serialVersionUID for this class. The serialVersionUID defines a set of classes all with the same name that have evolved from a common root class and agree to be serialized and deserialized using a common format. NonSerializable classes have a serialVersionUID of 0L.

Returns

• the SUID of the class described by this descriptor

public static ObjectStreamClass lookup (Class<?> cl)

Find the descriptor for a class that can be serialized. Creates an ObjectStreamClass instance if one does not exist yet for class. Null is returned if the specified class does not implement java.io.Serializable or java.io.Externalizable.

Parameters

cl	class for which to get the descriptor

Returns

• the class descriptor for the specified class

public static ObjectStreamClass lookupAny (Class<?> cl)

Returns the descriptor for any class, regardless of whether it implements Serializable.

Parameters

cl	class for which to get the descriptor

Returns

• the class descriptor for the specified class

public String toString ()

Return a string describing this ObjectStreamClass.

Returns

• a printable representation of this object.