import java.util.regex.*; /** * Call this program with two arguments; a regular expression and a string. The * program prints the text, from the string, that matches the first capturing * group in the regular expression. */ public class RegexExample { public static void main(String[] args) { String regex = args[0]; String content = args[1]; Pattern pat = Pattern.compile(regex); Matcher mat = pat.matcher(content); if (mat.matches()) { if (mat.groupCount() > 0) { System.out.println("Group 1: " + mat.group(1)); } else { System.out.println("Group: "); } } else { System.out.println("No match!"); } } }