NullPointerException when accessed with IE 8

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What steps will reproduce the problem?
1. startup IE8 (WinXP or Win7 doesn't matter)
2. access owl.cs.manchester.ac.uk/browser or your local instance of the 
ontology-browser

What is the expected output? 
the landing page of the servlet.

What do you see instead?
Internal Server Error 500
with the following error log:
java.lang.NullPointerException
    org.coode.www.servlet.AbstractOntologyServerServlet.doRequest(Unknown Source)
    org.coode.www.servlet.AbstractOntologyServerServlet.doGet(Unknown Source)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

What version of the product are you using? 
1.4.3 on Tomcat 6

On what operating system?
Ubuntu 10.04 LTS with all updates installed.

Please provide any additional information below.
I reproduced almost the same error with Firefox (13) and Chrome (with the 
slight difference, the in the serverlog it is stated, that the error occourred 
due to an unknown session ID), when I restarted the tomcat server during an 
active session. In both of them clearing the cookies and cache did the trick. 
In IE neither Private Mode nor clearing cache and cookies did the trick. 

Original issue reported on code.google.com by alex.sta...@googlemail.com on 11 Jul 2012 at 8:03

[GoogleCodeExporter]

I was wrong about the version used, it is 1.4.4 according to the landing page. 
Interesstingly I tryed to use the IE in different Versions (8,9) on different 
Machines (Win7) and somehow it seems to work for some combinations allthough 
the meassures take to clear the caches and the cookies were the same

Original comment by alex.sta...@googlemail.com on 12 Jul 2012 at 2:39

[GoogleCodeExporter]

With the Help of a colleague I was able to determine the cause of the issue. 
It seems that certain versions of IE (which is unfortunately very common with 
our research partners) send malformed mimetyp and request headers which causes 
the ontology-browser to return the NPE. To fix this one will have to add an 
null-pointer check in the 
owlbrowser/src/coode/www/servlet/AbstractOntologyServerServlet.java file.
in line 209. 
eg. 
OntologyBrowserConstants.RequestFormat r = 
OntologyBrowserConstants.RequestFormat.get(mime);
if (r != null)
return r;

in any other case which would be the case for the certain IE Versions html will 
be returned.

Best regards

Alex

Original comment by alex.sta...@googlemail.com on 15 Aug 2012 at 9:37

[GoogleCodeExporter]

Original comment by alex.sta...@googlemail.com on 15 Aug 2012 at 9:39

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