- * - * To allow subtypes of non-serializable classes to be serialized, the - * subtype may assume responsibility for saving and restoring the - * state of the supertype's public, protected, and (if accessible) - * package fields. The subtype may assume this responsibility only if - * the class it extends has an accessible no-arg constructor to - * initialize the class's state. It is an error to declare a class - * Serializable if this is not the case. The error will be detected at - * runtime.
- * - * During deserialization, the fields of non-serializable classes will - * be initialized using the public or protected no-arg constructor of - * the class. A no-arg constructor must be accessible to the subclass - * that is serializable. The fields of serializable subclasses will - * be restored from the stream.
- * - * When traversing a graph, an object may be encountered that does not - * support the Serializable interface. In this case the - * NotSerializableException will be thrown and will identify the class - * of the non-serializable object.
- * - * Classes that require special handling during the serialization and - * deserialization process must implement special methods with these exact - * signatures:
- * - *
- * private void writeObject(java.io.ObjectOutputStream out) - * throws IOException - * private void readObject(java.io.ObjectInputStream in) - * throws IOException, ClassNotFoundException; - * private void readObjectNoData() - * throws ObjectStreamException; - *- * - *
The writeObject method is responsible for writing the state of the - * object for its particular class so that the corresponding - * readObject method can restore it. The default mechanism for saving - * the Object's fields can be invoked by calling - * out.defaultWriteObject. The method does not need to concern - * itself with the state belonging to its superclasses or subclasses. - * State is saved by writing the individual fields to the - * ObjectOutputStream using the writeObject method or by using the - * methods for primitive data types supported by DataOutput. - * - *
The readObject method is responsible for reading from the stream and - * restoring the classes fields. It may call in.defaultReadObject to invoke - * the default mechanism for restoring the object's non-static and - * non-transient fields. The defaultReadObject method uses information in - * the stream to assign the fields of the object saved in the stream with the - * correspondingly named fields in the current object. This handles the case - * when the class has evolved to add new fields. The method does not need to - * concern itself with the state belonging to its superclasses or subclasses. - * State is saved by writing the individual fields to the - * ObjectOutputStream using the writeObject method or by using the - * methods for primitive data types supported by DataOutput. - * - *
The readObjectNoData method is responsible for initializing the state of - * the object for its particular class in the event that the serialization - * stream does not list the given class as a superclass of the object being - * deserialized. This may occur in cases where the receiving party uses a - * different version of the deserialized instance's class than the sending - * party, and the receiver's version extends classes that are not extended by - * the sender's version. This may also occur if the serialization stream has - * been tampered; hence, readObjectNoData is useful for initializing - * deserialized objects properly despite a "hostile" or incomplete source - * stream. - * - *
Serializable classes that need to designate an alternative object to be - * used when writing an object to the stream should implement this - * special method with the exact signature:
- * - *
- * ANY-ACCESS-MODIFIER Object writeReplace() throws ObjectStreamException; - *
- * - * This writeReplace method is invoked by serialization if the method - * exists and it would be accessible from a method defined within the - * class of the object being serialized. Thus, the method can have private, - * protected and package-private access. Subclass access to this method - * follows java accessibility rules.
- * - * Classes that need to designate a replacement when an instance of it - * is read from the stream should implement this special method with the - * exact signature.
- * - *
- * ANY-ACCESS-MODIFIER Object readResolve() throws ObjectStreamException; - *
- * - * This readResolve method follows the same invocation rules and - * accessibility rules as writeReplace.
- *
- * The serialization runtime associates with each serializable class a version
- * number, called a serialVersionUID, which is used during deserialization to
- * verify that the sender and receiver of a serialized object have loaded
- * classes for that object that are compatible with respect to serialization.
- * If the receiver has loaded a class for the object that has a different
- * serialVersionUID than that of the corresponding sender's class, then
- * deserialization will result in an {@link InvalidClassException}. A
- * serializable class can declare its own serialVersionUID explicitly by
- * declaring a field named "serialVersionUID" that must be static,
- * final, and of type long:
- * - *
- * ANY-ACCESS-MODIFIER static final long serialVersionUID = 42L; - *- * - * If a serializable class does not explicitly declare a serialVersionUID, then - * the serialization runtime will calculate a default serialVersionUID value - * for that class based on various aspects of the class, as described in the - * Java(TM) Object Serialization Specification. However, it is strongly - * recommended that all serializable classes explicitly declare - * serialVersionUID values, since the default serialVersionUID computation is - * highly sensitive to class details that may vary depending on compiler - * implementations, and can thus result in unexpected - *
InvalidClassExceptions during deserialization. Therefore, to
- * guarantee a consistent serialVersionUID value across different java compiler
- * implementations, a serializable class must declare an explicit
- * serialVersionUID value. It is also strongly advised that explicit
- * serialVersionUID declarations use the private modifier where
- * possible, since such declarations apply only to the immediately declaring
- * class--serialVersionUID fields are not useful as inherited members. Array
- * classes cannot declare an explicit serialVersionUID, so they always have
- * the default computed value, but the requirement for matching
- * serialVersionUID values is waived for array classes.
- *
- * @author unascribed
- * @see java.io.ObjectOutputStream
- * @see java.io.ObjectInputStream
- * @see java.io.ObjectOutput
- * @see java.io.ObjectInput
- * @see java.io.Externalizable
- * @since JDK1.1
- */
-public interface Serializable {
-}