The language maintainers have already decided to slow down string-construction by calling StringUTF16.compress(value) which checks if the input can be converted

The language maintainers have already decided to slow down string-construction by calling StringUTF16.compress(value) which checks if the input can be converted into LATIN1 and if so, creating a LATIN1 byte-array representation from the ground up. Compared to this, I wager that the incremental cost is small to verify that the coder matches the content. Also, depending on the implementation of string-interning and StringUTF16.compress, it's possible that the verification step is only needed for non-LATIN1 strings. Which according to the JEP is only a small minority of strings seen. If there is a cheaper solution, I'm certainly all for it. I'm just spitballing ideas here. But I don't think it is acceptable to allow "hello world".startsWith("hello") to return false.