Bad http.agent in Java properties : a bug in the HTTP user-agent string?

Question

Hi all,
Me :
I'm patching AWSTATS (web log analyzer tool) in order to recognize which Java version has
been used to download files.
Context of the problem :
Each time a Java program (or applet) is downloading a file (for example .class, .png, .html)
from a web server, a line will be added in the web server log file. If the web server is well
configured, the user agent used to download the file will be at the end of the line in the log file.
For Sun Java JVM, the user agent string is configured in the Java properties under "http.agent".
Usually, the user-agent string contains the word "Java" and the virtual machine version. In most
cases, this is just a string like "Java/1.4.2", so this is relatively easy to parse.
Problem :
Looking in my web server stats, and then on the web, I found that a JVM's user-agent is
"Mozilla/4.0 (Windows XP 5.1)", which obviously does not contains the word "Java".
Consequently, it is difficult to say that this user-agent string belongs to a JVM.
Further look in my log files and on google shows that this http.agent string appears
on Microsoft Internet Explorer (it seems MSIE 6.0) over Windows XP with the J2RE plugin:
http://board.gulli.com/thread/300321
http://forum.java.sun.com/thread.jsp?thread=531295&forum=30&message=2559523
http://forum.java.sun.com/thread.jsp?forum=63&thread=132769&start=210&range=15&tstart=0&trange=15
http://forum.java.sun.com/thread.jsp?forum=32&thread=480899
http://www.goodidea.ru/setupJava/javaInstall.htm
The J2RE plugin version does not seems to play a role as this user-agent string has
been seen on 1.4.1_02-b06, 1.4.2_01, 1.4.2_03 and 1.4.2_04-b05.
Further information requested :
I would like to know:
1) if you have reported the same problem;
2) if there is some rules for the http.agent property;
3) if this is a bug.
Thank you very much, and feel free to add you opinion.
Julien

Answer 1

The web log files where the "Mozilla/4.0 (Windows XP 5.1)" user-agent appears can be displayed using the following search terms on google :
"Mozilla/4.0 (Windows XP 5.1)" -"(Windows XP 5.1) Java"
http://www.google.ch/search?hl=fr&ie=UTF-8&q=%22Mozilla%2F4.0+%28Windows+XP+5.1%29%22+-%22%28Windows+XP+5.1%29+Java%22&btnG=Rechercher&meta=
Julien