Match and Partial Match for Regular Expression. The main idea of the algorithm is to get all substrings of the given regular expression Regex and to apply the method hitEnd() of the class java.util.regex.Matcher. If the examined string Input matches some substring of Regex then this substring Input can be completed to the string which is in full match to Regex. It is checked on 100 pairs (Input, Regex).-Match and Partial Match for Regular Expression. The main idea of the algorithm is to get all substrings of the given regular expression Regex and to apply the method hitEnd() of the class java.util.regex.Matcher. If the examined string Input matches some substring of Regex then this substring Input can be completed to the string which is in full match to Regex.　It is checked on 100 pairs (Input, Regex).