JFlex Home





  Mailing List  




SourceForge Logo
project summary
JFlex - The Fast Scanner Generator for Java


Current stable version is JFlex 1.4.3 released at Jan 31, 2009


[2009-01-31]     JFlex 1.4.3 released. See below for release notes.

[2008-05-27]     JFlex 1.4.2 released.

[2007-10-29]     There now exists a Maven JFlex plugin, contributed by Régis Décamps. It integrates JFlex into the Maven software project management tool.

What is it?

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.

Why should I use JFlex and not JLex? Well, you might want to take a look at the features of JFlex.

Is it free?

Yes. It is released under the GPL and available for free download. See also Copyright, License & Warranty. Code you generate with JFlex is not covered by the GPL, it is yours.

What's new in version 1.4.3?

Version 1.4.3 is a maintenance release fixing all known bugs of version 1.4.2. More detailed changes in version 1.4.3 are:

  • Fixed bug #2018299 (lookahead syntax error)
  • Fixed bug #2010261 (min_int in Java example scanner).
  • Fixed bug #2007221 (zzEOFDone not reset in yyreset(Reader))
  • Fixed bug #1999301 (%type and %int at the same time should produce error message)

See also the change log file for the complete list of changes.


What's new on these pages?

There is a list of files on this website ordered by modification date.

What platforms does JFlex support?

JFlex should run on any platform that supports a JRE/JDK 1.1 or above.

Java is a trademark of Sun Microsystems. JFlex is not sponsored by or affiliated with Sun Microsystems

most recently modified at 2009-01-31 12:33 UTC by Gerwin Klein