RFR: 8315810: Reimplement sun.reflect.ReflectionFactory::newConstructorForSerialization with method handles

[Mandy Chung]

On Wed, 6 Sep 2023 22:05:47 GMT, Chen Liang <liach at openjdk.org> wrote:

>> This reimplements `sun.reflect.ReflectionFactory::newConstructorForSerialization` with method handles.
>> 
>> This API currently generates the bytecode which fails the verification because `new C; invokespecial A()` where the given class `C` and invoke a no-arg constructor of `C`'s first non-`Serializable` superclass `A` is not a valid operation per the VM specification. VM special cases the classes generated for reflection to skip verification for the constructors generated for serialization and externalization.  This change will allow such VM hack to be removed.
>> 
>> A `jdk.reflect.useOldSerializableConstructor` system property can be set to use the old implementation in case if customers run into any compatibility issue.   I expect this change has very low compatibility risk.   This system property is undocumented and will be removed in a future release.
>
> src/java.base/share/classes/jdk/internal/reflect/MethodHandleAccessorFactory.java line 127:
> 
>> 125:     static ConstructorAccessorImpl newSerializableConstructorAccessor(Class<?> decl, Constructor<?> ctor) {
>> 126:         if (!constructorInSuperclass(decl, ctor)) {
>> 127:             throw new UnsupportedOperationException(ctor + " not a superclass of " + decl.getName());
> 
> Notice in JShell 20, you could do this:
> 
> jshell> import sun.reflect.ReflectionFactory;
> jshell> var rf = ReflectionFactory.getReflectionFactory()
> jshell> var c = rf.newConstructorForSerialization(String.class, Boolean.class.getConstructor(boolean.class))
> jshell> String d = (String) c.newInstance(false)
> jshell> d.length()
> 
> which ends up in an NPE for `d.value` is null. This UOE is technically a new behavior that should be mentioned in the CSR.

good catch.  will update the CSR.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15600#discussion_r1317900597