One example that has provided me benefit multiple times is a simple Java application that I can run against a String I’m considering as a regular expression token to be used with String.split.

StringUtils for splitting and joining strings with support for separatorCharacter and escapeCharacter. - StefH/string-split-join ...

While the "split" method on strings may be more common, it does not handle regular expressions, while the Java and Perl counterparts do. For comparison, there's also a test case for this ...

I have previously blogged on how Groovy and ActionScript provide demonstrations of switching on Strings functionality that has not been available in Java. JDK 7 changes this for Java by ...