RFR: JDK-8068721 - RMI-IIOP communication fails when ConcurrentHashMap is passed to remote method

[Mark Sheppard]

Hi
     based on feedback webrev has been updated as follows:

http://cr.openjdk.java.net/~msheppar/8068721/jdk9/corba/webrev.01/
http://cr.openjdk.java.net/~msheppar/8068721/jdk9/jdk/webrev.01/

regards
Mark

On 23/03/2015 21:25, Mark Sheppard wrote:
> Hi
>  please oblige and review the following fix
>
> http://cr.openjdk.java.net/~msheppar/8068721/jdk9/corba/webrev/
> http://cr.openjdk.java.net/~msheppar/8068721/jdk9/jdk/webrev/
>
>
> which addresses the issue in
> https://bugs.openjdk.java.net/browse/JDK-8068721
>
> This relates to RMI-IIOP and the interplay between custom marshalling 
> of ValueTypes and
> the corresponding serialization of a Java class, in this case 
> ConcurrentHashMap.
>
> ConcurrentHashMap changed its structure in jdk8 from that used in jdk7.
> This resulted in modification to the readObject and writeObject methods,
> and in particular, former serial fields were removed, resulting in
> writeObject using PutField and readObject using defaultReadObject.
> The writeObject invokes the putFields method of an ObjectOutputStream 
> multiple times, and assumes
> that it will receive the same PutField object instance for each 
> invocation. The spec
> doesn't endorse this behaviour - but that's what the implementation of 
> ObjectOutputStream
> provides. However in the case of RMI-IIOP, the OutputStreamHook, a 
> subclass of ObjectOutputStream, returns a new instance for each
> putFields invocation. Thus, the ConcurrentHashMap writeObject results 
> in improper serialization in the context
> of RMI-IIOP.
> In the unmarshalling flow of ConcurrentHashMap, the readObject now 
> uses defaultReadObject rather than GetField
> In this call flow the IIOPInputStream attempts to ignore any primitive 
> field, in the serialized data, that doesn't
> correspond with a reflective field of the object. However, it leaves 
> the primitive in the stream.
> Thus, in the case of ConcurrentHashMap, which has serialized two 
> integers and
> an array of Segments (subclass of ReentrantLock), this results in 
> erroneous
> deserialization, with a misinterpretation of a value tag in the stream 
> as an array length
> and an attempt to allocate a very large array ensues, with an 
> exception being thrown.
>
> The OutputStreamHook now returns the same instance of PutField 
> allocated for each separate call of putFields method.
> This highlights a need to tighten up and disambiguate the 
> OutputObjectStream spec for putFields.
>
> IIOPInputStream now removes the primitive values from the stream.
>
> regards
> Mark