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...