[throwawaykf05]

The ABI, being essentially an ordering of bytes at specific offsets, has no expressive capability. Tons of creativity, sure, but of the functional kind, the stuff copyright explicitly exempts.

Note that if only ABI compatibility was required, Google could very well have defined their own API. For instance, they could have defined an API called "openFile()" that compiles down to the exact byte code as "new java.io.File()". But they were not after binary interoperability, they were after the Java developer base Sun had spent billions building.

[gpderetta]

An ABI is certainly not just an ordering of bytes at a specific offsets, no more than a text file is just a long string of bytes. There are very specific semantics assigned to those bytes.

[throwawaykf05]

Yes, and those semantics are purely functional, lacking any form of expression, which copyright expressly excludes from protection. The only reason binaries are copyright-protected is because they are "derivative works" from the original copyright-protected program code.