That clause (which was a more general restriction on use in safety-critical systems) was definitely part of the Java EULA pre-OpenJDK, but I'd imagine that it was more widespread. As I understand it, it was very much a liability issue for Sun (not to mention the PR nightmare of being in any way a cause of a nuclear accident). If you wanted you could pay them a great deal of money to accept that liability, but they wouldn't do it for free.