On Tue, 27 Aug 2024 20:45:50 GMT, David M. Lloyd <d...@openjdk.org> wrote:
>> Issue [JDK-8164908](https://bugs.openjdk.org/browse/JDK-8164908) added >> support for functionality required to continue to support IIOP and custom >> serializers in light of additional module-based restrictions on reflection. >> It was expected that these libraries would use `sun.misc.Unsafe` in order to >> access fields of serializable classes. However, with JEP 471, the methods >> necessary to do this are being removed. >> >> To allow these libraries to continue to function, it is proposed to add two >> methods to `sun.reflect.ReflectionFactory` which will allow serialization >> libraries to acquire a method handle to generated `readObject`/`writeObject` >> methods which set or get the fields of the serializable class using the >> serialization `GetField`/`PutField` mechanism. These generated methods >> should be used by serialization libraries to serialize and deserialize >> classes which do not have a `readObject`/`writeObject` method or which use >> `ObjectInputStream.defaultReadObject`/`ObjectOutputStream.defaultWriteObject` >> to supplement default serialization. >> >> It is also proposed to add methods which allow for the reading of >> serialization-specific private static final fields from classes which have >> them. >> >> With the addition of these methods, serialization libraries no longer need >> to rely on `Unsafe` for serialization/deserialization activities. >> cc: @AlanBateman > > David M. Lloyd has updated the pull request incrementally with two additional > commits since the last revision: > > - Eliminate cache > - Rework using facilities found in ObjectStreamClass > > This variation has the disadvantage of requiring a couple temporary arrays > to be allocated each time the method handles are used. No need to create multiple `MethodHandles.Lookup` objects in the static initialiser: src/java.base/share/classes/java/io/ObjectStreamDefaultSupport.java line 50: > 48: DRO_HANDLE = > MethodHandles.lookup().findStatic(ObjectStreamDefaultSupport.class, > "defaultReadObject", droType); > 49: MethodType dwoType = MethodType.methodType(void.class, > ObjectStreamClass.class, Object.class, ObjectOutputStream.class); > 50: DWO_HANDLE = > MethodHandles.lookup().findStatic(ObjectStreamDefaultSupport.class, > "defaultWriteObject", dwoType); Suggestion: var lookup = MethodHandles.lookup(); MethodType droType = MethodType.methodType(void.class, ObjectStreamClass.class, Object.class, ObjectInputStream.class); DRO_HANDLE = lookup.findStatic(ObjectStreamDefaultSupport.class, "defaultReadObject", droType); MethodType dwoType = MethodType.methodType(void.class, ObjectStreamClass.class, Object.class, ObjectOutputStream.class); DWO_HANDLE = lookup.findStatic(ObjectStreamDefaultSupport.class, "defaultWriteObject", dwoType); ------------- PR Review: https://git.openjdk.org/jdk/pull/19702#pullrequestreview-2264666938 PR Review Comment: https://git.openjdk.org/jdk/pull/19702#discussion_r1733657524
