Getting Started With FLEX

Here are the steps for setting the configuration files and having the Flex infrastructure running on your machine. There are instructions for using Flex sources or binaries downloaded from the web (Flex home page), or for using the CVS archive on

You can either download the highlighted files, or you can alternatively click the files, then cut and paste to the appropriate .rc file (for configuration files) or run the commands (for the checkout).

0. Decide what version of FLEX you want.

As of this writing, FLEX is at version 3.2+ (that is, version 3.2 has been released and work is continuing on the 'next' version, whatever that will be). However, current development on FLEX uses the GJ extensions to Java which are not (yet!) an official part of the Java language. Therefore, some people will want to use version 3.1, which was the last released version before the adoption of GJ. FLEX 3.1 also doesn't use the 'assert' keyword introduced with Sun's JDK 1.4 release, and so may be attractive for that reason as well. FLEX 3.2 is a stable release using the assert keyword and GJ features, and you can download the most recent unstable version from CVS if you like.

If you grab sources/binaries from the web, make sure you are getting the proper version of FLEX. If you fetch FLEX using CVS, then the following CVS tags correspond to released versions of FLEX:

FLEX versionCVS tag
You will use this tag in step 3, below.

CVS BUG ALERT: Using HEAD as a tag in CVS doesn't actually work correctly. If you want to check out the HEAD release of FLEX from CVS, substitue '-A' for '-r HEAD' in any CVS command you use.

1. Using FLEX sources/binaries downloaded from the web

You can download either the FLEX sources and compile them or you can directly download the compiled sources. Both FLEX sources and binaries are available on the web from the FLEX home page.

2. Setting up the configuration files

3. Using FLEX sources from the CVS archive on

Replace <cvs tag> in the below with the CVS tag corresponding to the version of FLEX you would like to fetch, as described in step 0.

CVS BUG REMINDER: Using HEAD as a tag in CVS doesn't actually work correctly. If you want to check out the HEAD release of FLEX from CVS, substitue '-A' for '-r HEAD' in any CVS command you use.

4. Compiling the sources

5. Installing GNU Classpath

Although this is not required to use FLEX for analysis, if you wish to compile executables with FLEX you will need to install the GNU project's implementation of the Java standard class libraries. Information on how to do so is on its own page.

6. Testing everything went OK

7. Doing more

You probably want to go on now to checkout and build the Runtime which will walk you through the steps to build an actual running executable from a Java program. Be sure to read the README and REQUIRED files in the Runtime module. If you selected FLEX version 3.2 or later in step 0, then you probably also want to read this information on getting and using the GJ compiler in order to be maximally productive.

Finally, if you're interested in working with our Real-time Java implementation, you will want to go on to install and build the Realtime code.

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