Pattern matching using "regular expressions" can help automate a number of
text-processing operations like search and replace, input validation, text
conversion, and filters. What otherwise requires significant amounts of code
can be done in just a few lines with regular expressions because of the
powerful underlying regular expressions processing engine. Some programming
languages such as Perl and operating systems utilities such as grep have
supported regular expressions for a number of years. But before J2SE 1.4,
Java (J2SDK) didn't support it and one had to use external packages like
Jakarta Regexp, IBM's commercial package (com.ibm.regex). Thankfully that
changed with the introduction of the java.util.regex package. The package
provides standard implementations for... (more)