Many reasons, e.g. You want people to use your API, but not reimplement it. Or you want to allow people to use your API for specific use cases without paying, b

Many reasons, e.g. You want people to use your API, but not reimplement it. Or you want to allow people to use your API for specific use cases without paying, but want money for others. Sun wanted the second one, Google thought they could get away with ignoring that and now someone has to sort out the fallout and make a decision.