Custom 404 Page Using JBOSS

Missing PuzzleHaving a custom “page not found”, or 404 page, is an important modification for any website.  It’s used to enhance the user experience by presenting an easy to understand message.

Setting up a user friendly error page is simple enough using Apache web server.  Just modify the line in httpd.conf and point it to a static HTML document:

ErrorDocument 404 /the404_page.html

With JBOSS (or Tomcat-like Java container) application server, it’s slightly trickier.  It has to be handled per web application basis.  The change is done on the web.xml file, with these entries:

<web-app>

<error-page>
<error-code>404</error-code>
<location>/the404_page.html</location>
</error-page>

</web-app>

For the root directory, modify the web.xml in the ./deploy/jboss-web.deployer/ROOT.war/WEB-INF directory.

Testing this setup in Firefox and Opera, the custom 404 page will automatically show up properly.

However, with Internet Explorer, a “The Webpage Cannot Be Found” message comes up instead.  This is a feature of IE to show Microsoft’s version of a “friendlier error message”.  In this case, we want to disable it, so the custom 404 page will show up.  It can be done via Internet Options -> Advanced tab :

Option in IE to Supress Custom 404 Error Page

Update: Microsoft Help & Support site states if the 404 error page is greater than 512 bytes, then IE will not show the friendly message.  So the page size must be a bigger one, not just a simple one liner.

Now that the applications are setup to serve up custom error page, here are some examples of beautiful 404 page designs to improve the user experience.

SSL From Java Client

java_sslI’ve described a way to install a self-signing SSL certificate using OpenSSL for testing purposes.  When connecting to a web server using a web browser client, it is straight forward to add the “fake” certificate (just follow the instructions on the browser screen).  However, in a Java application, it’s a little bit more work.

The procedure is the following:

  • Obtain the SSL certificate from the website administrator.  Alternatively, use the browser:
  1. Browse the URL, for example:  https://www.testmachine.com
  2. When the security window popup appears, just click ‘continue’.
  3. The browser has an option to view the certificate.  With Internet Explorer 7, next to the Address Bar there’s a “Certificate Error” button.  Press that and view certificate.  With Firefox, click on the yellow lock at the bottom of the screen.
  4. Go to the Details tab.
  5. Click on “Copy to File”.  In Firefox, click on the “Export” button.
  6. Save the file as “website.cert”
  • Copy the Cert file to where the Java client is going to be executed.
  • Go to the JRE (Java Run Time) library under lib/security, for example: /usr/local/jdk_1.4.3/jre/lib/security/
  • The certs are stored in a file called “cacerts”.
  • Run the keytool app to import the “website.cert” file that was exported earlier from a web browser:

keytool -import -alias websiteAlias -keystore cacerts -file website.cert

  • Enter the default password: changeit
  • Check the content of the new “cacerts” file using:

keytool -list -keystore cacerts

  • Test it.   If it’s a web container (i.e. Tomcat), restart the JVM.

Webapper site has a short Java client test code, and a quick procedure to compile/run a client to test it.