Hello everyone! When the input of a j.u.regex.Matcher is restricted with .region() method, it can possibly cut off a half of a surrogate pair. It turns out that greedy matching implemented in the Pattern.CharPropertyGreedy class fails to recognize this edge case in two scenarios: 1) When it greedily consumes the input and meets a higher half of a surrogate pair that was cut off at the end of input, and 2) When it backs off and meets a lower half of a surrogate pair at the very beginning of input. In both cases, the engine reads the entire codepoint, crossing the boundaries of the set region. Instead, it should only read the half of the surrogate pair that lies inside the region and ignore the other half. Would you please help review the fix? BUGURL: https://bugs.openjdk.java.net/browse/JDK-8237599 WEBREV: http://cr.openjdk.java.net/~igerasim/8237599/00/webrev/ Thanks in advance! -- With kind regards, Ivan Gerasimov