Enum constants are deserialized differently than ordinary serializable or * externalizable objects. The serialized form of an enum constant consists @@ -241,9 +239,16 @@ * Java Object Serialization Specification, Section 1.13, * "Serialization of Records" for additional information. * - *
Value classes are {@linkplain Serializable} through the use of the serialization proxy pattern. - * See {@linkplain ObjectOutputStream##valueclass-serialization value class serialization} for details. - * When the proxy is deserialized it re-constructs and returns the value object. + *
Serialization and deserialization of value classes is described in - * {@linkplain ObjectOutputStream##valueclass-serialization value class serialization}. - * - * @implSpec - * When enabled with {@code --enable-preview}, serialization and deserialization of - * Core Library value classes migrated from pre-JEP 401 identity classes is - * implementation specific. - * *
Exceptions are thrown for problems with the InputStream and for * classes that should not be deserialized. All exceptions are fatal to * the InputStream and leave it in an indeterminate state; it is up to the * caller to ignore or recover the stream state. * + *
An object in the stream that instantiates or extends a Serializable + * {@linkplain Class#isValue value class} can only be deserialized if + * it is a record or a boxed primitive value. Otherwise, + * {@code readObject} throws an {@code InvalidClassException}. + *
Enum constants are serialized differently than ordinary serializable or * externalizable objects. The serialized form of an enum constant consists @@ -163,35 +157,19 @@ * defaultWriteObject and writeFields initially terminate any existing * block-data record. * - * *
Records are serialized differently than ordinary serializable or externalizable * objects, see record serialization. * - * - *
Value classes are {@linkplain Serializable} through the use of the serialization proxy pattern. - * The serialization protocol does not support a standard serialized form for value classes. - * The value class delegates to a serialization proxy by supplying an alternate - * record or object to be serialized instead of the value class. - * When the proxy is deserialized it re-constructs the value object and returns the value object. - * For example, - * {@snippet lang="java" : - * value class ZipCode implements Serializable { // @highlight substring="value class" - * private static final long serialVersionUID = 1L; - * private int zipCode; - * public ZipCode(int zip) { this.zipCode = zip; } - * public int zipCode() { return zipCode; } - * - * public Object writeReplace() { // @highlight substring="writeReplace" - * return new ZipCodeProxy(zipCode); - * } - * - * private record ZipCodeProxy(int zipCode) implements Serializable { - * public Object readResolve() { // @highlight substring="readResolve" - * return new ZipCode(zipCode); - * } - * } - * } - * } + *
{@linkplain Class#isValue Value classes} that are not records cannot be + * serialized directly. To serialize an instance of a value class, the + * + * {@code writeReplace} method can provide a proxy object instead. That + * object can then be serialized, and used to reconstruct the expected value + * class instance at deserialization time. + *
Serialization and deserialization of value classes is described in - * {@linkplain ObjectOutputStream##valueclass-serialization value class serialization}. - * *
Exceptions are thrown for problems with the OutputStream and for * classes that should not be serialized. All exceptions are fatal to the * OutputStream, which is left in an indeterminate state, and it is up to * the caller to ignore or recover the stream state. * + *
An object that instantiates or extends a Serializable + * {@linkplain Class#isValue value class} can only be serialized if + * it is a record, or it implements {@code writeReplace}, or it is + * a boxed primitive value. Otherwise, {@code writeObject} throws an + * {@code InvalidClassException}. + *
* - * Value classes can implement {@code Serializble} and receive the treatment defined - * by the - * Java Object Serialization Specification, Section 1.14, - * "Serialization of Value Objects". Any declarations of the special - * handling methods discussed above, except {@code writeReplace}, - * are ignored for value classes. Value classes implementing {@link Externalizable} - * and not using {@code writeReplace} are not supported.
+ *
{@linkplain Class#isValue Value classes} that are not records can + * implement {@code Serializable}, but cannot be serialized directly. Instead, + * the {@code writeReplace} method should be used to designate an alternative + * object for serialization. At deserialization time, the alternative object + * can implement {@code readResolve} to construct the expected value class + * instance. + *
{@linkplain Class#isValue Value classes} that are not records cannot be + * deserialized directly. To serialize an instance of a value class, a proxy + * object should be used instead. That object can then implement + * + * {@code readResolve} to construct and return the expected value class + * instance. + *