The links in the question are back. No cause for panic (at least as of now).
This might apply only to users of a particular tag (Java) in StackOverflow.
I just noticed that the Java Language Specification is no longer available on the Oracle Technology Network.
There are questions (and lots of answers; ask Jon Skeet if you must) in the Java tag that reference this specification, and may even link to it.
How does one deal with the now possibly redundant links?