String Related types and classes

String
The basic class for strings. String objects can NOT be changed.

char
Primitive type for 16-bit Unicode characters.

Character
Primarily useful for its utility functions for working with characters.

StringBuffer
StringBuffers are used to build or change strings. Conversion between String and StringBuffer is easy.

StringBuilder
StringBuilder was added in Java 5. It is the same as StringBuilder, but slightly faster because it's unsynchronized.

StringTokenizer
Used to break a String into tokens (words).

BufferedReader
BufferedWriter
Useful for reading and writing text files.

Pattern, Matcher
JDK 1.4 added java.util.Pattern and Matcher to do regular expression matching.