Green_Shade: Fair enough, though they certainly do not consider fan-made emulators illegal, see the widespread DOSBox usage. But GoG definitely are (traditionally anyway) dedicated to Microsoft platforms, with Mac and Linux support that seems liable to change, especially with Defender of the Crown including the Amiga version (with emulator, though they have said this is limited to this publisher and not a long-term thing.)
HijacK: They received permissions for the Amiga version they released. Also, DOSbox is approved by MS, so it cannot be classified as illegal no matter how hard people try to make it seem so.
I dunno about Java though - I mean its MEANT to be portable and run in a VM and that, I'm not sure it would even truly be a emulator and not a specialised VM, don't know if it infringes on anything Oracle's end though...
But in any case, I would say that until the day comes that GOG releases an old Java based phone game, or includes one as an 'extra' that its pretty safe to assume that its not something that GOG is wanting to spend its time on, legal issues or not and doesn't really have any place on the list