Pattern-Matcher-issue-with-special-characters-in-Java Regular Expression (Regexp) in Java Introduction : Regular Expression (regexp) is extremely useful in programming, especially in processing text files. The “ Sun's online Java Tutorial ” trail on " Regular Expressions " is excellently written. Please read if you are new to regexe. java.util.regex.Pattern&java.util.regex.Matcher(JDK 1.4): Regular expression was introduced in Java 1.4 in package java.util.regex . This package contains only two classes: Pattern and Matcher. The Pattern class represents a compiled regular expression. You get a Pattern object via static method Pattern.compile(String regexe) . The resulting Pattern object is used to obtain a Matcher instance, which is used to parse the input source. Ex: String regexe = "......"; String input = "......"; Pattern pattern Pattern.compile(regex