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Ordering of members in Oracle/Google Java copyright lawsuit

November 2nd, 2010

Oracle have specified some details in their ‘Java’ copyright claims against Google. One item that caught my eye was the source of a class copyrighted by Oracle and the corresponding class being used by Google. An experiment I ran at the 2005 and 2008 ACCU conferences studied how developers create/organize data structures from a given specification and sheds some light on developer behavior in this area (I am not a lawyer and have never been involved in a copyright case, so I will not say anything about legal issues).

Two of the hypothesis investigated by the ACCU experiment were, 1) within aggregate types (e.g., structs or classes) members having the same type tend to be placed together (e.g., all the chars followed by all the ints followed by all the floats), and 2) the relative ordering of members follows the order of the corresponding items in the specification (e.g., if the specification documents the date and then the location and this information occurs within the same structure the corresponding date member will appear before the location member).

The first hypothesis was investigated by analyzing C source source and found that members having the same type are very likely to be grouped together. Looking at the private definitions in the Oracle code we see that members having a HashSet or boolean type are not grouped together with other members of the same type; one possibility was that the class grew over time and new members were appended rather than intermixed with members already present. The corresponding Google code also has the HashSet or boolean intermixed with members having different types. At least one implementation exists where members having the same type are grouped together.

The second hypothesis was investigated by running an experiment which asked developers to create an API from a specification, with everybody seeing the same specification except the ordering of the information was individually randomized for each developer. The results showed that when creating a struct or class (each subject was allowed to create the API in a language of their choice, with C, C++ and Java actually being used) developers tended to list members in the same relative order as the information appeared in the specification.

If the Apache implementors of the code used by Google based their specification on the Oracle code, it is to be expected that the ordering of the members would be very similar, which is it.

There has been a lot of talk of clean room implementation being used for the Java-like code within Dalvik. Did somebody sit down and write a specification of the Oracle PolicyNode class that was then given to somebody else to implement?

The empirical evidence (i.e., members having the same type are not adjacent but intermixed with other types and relative member ordering is the same) suggests that the implementation of at least the private members of the PolicyNode class being used by Google was based directly on the Oracle code.

These members are defined to be private so Google cannot argue that they are part of an API (various people are claiming that being part of an API has some impact on copyright, I have no idea if this is true).

Can Google get around any copyright issue simply by reordering the member definitions? I have no idea.

It would appear that like the patent lawsuit this copyright lawsuit could prove to be very interesting to watch.

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