JFlex is a lexical analyzer generator (also known as scanner
generator) for Java(tm), written in Java(tm). It is also a
rewrite of the very useful tool JLex which was developed by
Elliot Berk at Princeton University. As Vern Paxson states
for his C/C++ tool flex: They do not share any code though.
JFlex is designed to work together with the LALR parser
generator CUP by Scott Hudson, and the Java modification of
Berkeley Yacc BYacc/J by Bob Jamison. It can also be used
together with other parser generators like ANTLR or as a
standalone tool.