Pattern Patterns are compiled regular expressions. If you need to do a lot of work with the same regular expression, it may be more efficient to compile it once and reuse it.
Matcher The result of applying a Pattern to a given input.
StringTokenizer Break a string into tokens according to delimiters.
Scanner Parses a text string of primitive types and strings. It supports localized numbers and various radixes.
String.matches, String.replaceAll, String.split In many cases, convenience methods such as String.matches, String.replaceAll and String.split will be preferable.
