JCas - Frequently Asked Questions

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JCas User Guide

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        JLL - JAAS Login Library


        Release Notes
        JCas Configuration
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JCas Developers

        API Javadocs
        CAS Specification

Table Of Contents

  1. What is JCas?
  2. What is CAS?
  3. How is JCas licensed?
  4. How is the JCas Project organized?
  5. How do I find out about future releases of JCas?
  6. How do I run JCas?
  7. What build should I download?
  8. Which operating systems does JCas support?
  9. I have downloaded JCas, but it won't start. How do I start it?
  10. Where are the JCas manuals?
  11. How do I ask questions?
  12. How do I report a bug?
  13. How do I make feature requests?
  14. How do I uninstall JCas?

What is JCas?

JCas is an Open Source server-side implementation of the CAS protocol. It provides extensive authentication methods for JDBC databases and a special connector for JAAS based authentication. Thus, JCas is most flexible due to the fact that it can be extended by just plugging in third-party JAAS providers.

What is CAS?

CAS is a protocol for distributed authentication and authorization. It is aimed at distributed applications that need to integrate various user interfaces into one single point of authentication. See the Specification of CAS/1.0 for more details.

How is JCas licensed?

JCas is published under the General Public License. There is no restriction regarding distribution, usage or modification as long as the origins of the software is made clearly visible to all users. We do not force our users to mention JCas anywhere in their user interfaces, but would be happy if you do so.

How is the JCas Project organized?

Currently, JCas is organized as a one-man-show. If you like to contribute in the effort to make distributed computing easier, feel free to join the development process (see section Get Involved).

How do I find out about future releases of JCas?

There are four possibilities:

How do I run JCas?

JCas is a full Java implementation. Make sure that JCas JAR archive, all JDBC drivers and JAAS provider classes are available through CLASSPATH variable. Then issue the following command:
    java jcas.JCasServer <path-to-config-file>
If the configuration file is correct and all other prerequisites (e.g. listener port is available) then JCas will startup and run.

What build should I download?

Use the source release if you need to adopt requirements that JCas cannot fulfill at the moment. If you want to use JCas "as-is" and just need to add your JDBC and/or JAAS providers, then you are fine downloading a binary release.

There is no documentation shipped with the releases so far, but it propably will come shortly. You should go to our website if the release of your version does not include proper documentation or if you got questions not answered in the shipped documentation. Also refer to our help forum.

Download the latest build available. We do not release nightly builds so far. Refer to the download section.

Which operating systems does JCas support?

JCas is not bound to a specific Operating System but to Java 1.4 Virtual Machine. Additionally you might need JDBC drivers and JAAS provider classes to work with JCas. Please be aware that these external classes might be coded platform-specific and therefore bound to these platforms. You better stick to native Java drivers to keep your server independent of the Operating System.

I have downloaded JCas, but it won't start. How do I start it?

Make sure you've downloaded the latest version and installed it correctly (although there can't usually be done anything wrong). Check if you have a correct Java version running (at least Java 1.4.2 is required). Make sure that all third-party classes are available at runtime (JCas JAR file, JDBC drivers, JAAS provider packages) and those classes can run on the system you are using.

Next check the configuration file. JCas will help you on that by telling you the reason for aborting startup.

Check the manual pages (see next section), help forum and bug tracking system if your problem is described there. If you can't find it, issue a question on our help forum (see below).

Where are the JCas manuals?

All documentation can be found in JCas releases. Latest documentation is available on our homepage The User's Guide will help you to configure JCas for your specific needs.

How do I ask questions?

The User Help Forum is created for that special purpose. Post your question there. We watch this forum on a daily basis and will answer questions as soon as they arrive.

How do I report a bug?

The JCas Project uses Sourceforge's standard bug tracker as its bug tracking system. Entering a bug report is as simple as filling in a web form on the JCas Bug Tracking page. The first time you enter a bug you should create a new Sourceforge account for yourself by providing an email address and choosing a password but anonymous reports are welcome either. If reported anonymously, please provide an e-mail address so we can contact you in case of questions or problems.

But wait! Before you enter a bug report, search the system to see if someone else has already entered a bug report similar to yours. If you find a bug report that outlines the problem you are seeing, you can simply annotate it with your comments to let the developers know that you have also hit the bug.

Once you have searched and not found anything, you can go ahead and enter a new bug report.

To make your bug report more helpful include the following in all bug reports you submit:

  1. The JCas build you are using, for example, JCas/0.1.0
  2. Your computer's specifications (OS, memory, other pertinent info)
  3. The contents of your .log file (or lack thereof). This is especially important if you get a message that reports an internal error.
  4. The Java runtime or development kit you are using to run JCas (use java -fullversion)
  5. A description of what you were doing when you encountered the bug
  6. An explanation of how the observed behavior differs from the expected behavior
  7. Step-by-step instructions that repeatedly expose the bug, so that the developer can see it for themselves.

How do I make feature requests?

Feature requests can be made through Sourceforge.

But wait! Just like with bug reports, you should first search Sourceforge to make sure that nobody has already made a similar request. If the feature request already exists simply annotate it with your comments.

When entering feature requests, please attempt to be very specific about the feature you would like, its use cases, and possible pitfalls that the implementor should avoid.

How do I uninstall JCas?

If you installed all files in one directory on your system, then simply delete it. No other tasks have to be performed.