Immutable implies thread safe. Somewhere in the concurrency section of Effective Java, it both that this is true and that documenting a class as immutable is go

Immutable implies thread safe. Somewhere in the concurrency section of Effective Java, it both that this is true and that documenting a class as immutable is good enough to document that it's thread safe. Not sure if the spec lays it out, but it's a consequence of the spec.