I see many blog posts mention a Streams class and I see it was once part of the lambda branch API. It appears to be non-public API now and it does not match the previous implementation. Is there a different way to do Streams.concat() or to append multiple values to a stream?
The Streams class got split and some of its methods were moved to StreamSupport, which does not contain a concat method in the latest build. The rationale for the split is explained here.
The specific case of concat has been mentioned separately in this post where it was proposed for removal and was apparently removed.
However a later post seems to indicate that it will reappear in future builds.
来源：https://stackoverflow.com/questions/16780647/java-8-java-util-stream-streams