Java: detect control characters which are not correct for JSON

Question

I am reinventing the wheel and creating my own JSON parse methods in Java.

I am going by the (very nice!) documentation on json.org. The only part I am unsure about is w

Answer 1

I know the question has been asked a couple of years ago, but I am replying anyway, because the accepted answer is not correct.

Character.isISOControl(int codePoint) 

does the following check:

(codePoint >= 0x00 && codePoint <= 0x1F) || (codePoint >= 0x7F && codePoint <= 0x9F);

The JSON specification defines at https://tools.ietf.org/html/rfc7159:

7. Strings

   The representation of strings is similar to conventions used in the C family of programming languages. A string begins and ends with quotation marks. All Unicode characters may be placed within the quotation marks, except for the characters that must be escaped: quotation mark, reverse solidus, and the control characters (U+0000 through U+001F).

Character.isISOControl(int codePoint) 

will flag all characters that need to be escaped (U+0000-U+001F), though it will also flag characters that do not need to be escaped (U+007F-U+009F). It is not required to escape the characters (U+007F-U+009F).