Class ObjectStreamClass

java.lang.Object
java.io.ObjectStreamClass
All Implemented Interfaces:
Serializable
public final 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 Java Object Serialization Specification, Section 4.6, "Stream Unique Identifiers".

Since:
1.1
External Specifications
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final ObjectStreamField[]
    NO_FIELDS
    serialPersistentFields value indicating no serializable fields

  • Method Summary

    Modifier and Type
    Method
    Description
    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.

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Creates and returns a copy of this object.
    boolean
    equals(Object obj)
    Indicates whether some other object is "equal to" this one.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Finalization is deprecated and subject to removal in a future release.
    final Class<?>
    getClass()
    Returns the runtime class of this Object.
    int
    hashCode()
    Returns a hash code value for this object.
    final void
    notify()
    Wakes up a single thread that is waiting on this object's monitor.
    final void
    notifyAll()
    Wakes up all threads that are waiting on this object's monitor.
    final void
    wait()
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
    final void
    wait(long timeoutMillis)
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
    final void
    wait(long timeoutMillis, int nanos)
    Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

  • Field Details

    • NO_FIELDS

      public static final ObjectStreamField[] NO_FIELDS
      serialPersistentFields value indicating no serializable fields

  • Method Details

    • lookup

      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

    • lookupAny

      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
      Since:
      1.6

    • getName

      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

    • getSerialVersionUID

      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

    • forClass

      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

    • getFields

      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.
      Since:
      1.2

    • getField

      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.

    • toString

      public String toString()
      Return a string describing this ObjectStreamClass.
      Overrides:
      toString in class Object
      Returns:
      a string representation of the object