String manipulation is probably one of the most frequently used operations. StringUtil adds more string operations.

replace replaces the occurrences of a certain pattern in a string with a replacement string. It has a variant with string arrays that replaces multiple strings at once.

replaceFirst, replaceIgnoreCase, replaceLast methods are few self-explanatory variants of previous method.

indexOf, indexOfIgnoreCase have many useful variants, too, such as searching for the string range.

lastIndexOf, lastIndexOfIgnoreCase methods are few self-explanatory variants of previous methods.

convertCharset converts string from one charset to another.

remove, removeChars removes characters or substrings from a string.

split, splitc works similar to StringTokenizer, maybe just a bit faster and more configurable.

capitalize and uncapitalize are two frequently used methods.

replace, replaceFirst, replaceLast, replaceIgnoreCase are all methods that performs replacing in various ways.

And so on...