Summary: When running JBoss 4.2 through an AJP/1.3 connector, JBoss 4.2 sends meaningless redirects to HTTP/1.0 clients if they didn't include Host header.
I'm running Debian Linux "etch" with Sun's JDK 1.6u11, Apache2.2 + mod_jk, JBoss 4.2.3 (JDK 6 version). I've created a simple webapp directory in the deploy folder named ROOT.war, and it includes a single file named index.jsp with this contents:
<% response.sendRedirect("/test"); %>
jbosstest:~# telnet localhost 80 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. GET / HTTP/1.0 HTTP/1.1 302 Moved Temporarily Date: Thu, 22 Jan 2009 17:04:53 GMT Server: Apache/2.2.3 (Debian) mod_jk/1.2.18 X-Powered-By: Servlet 2.4; JBoss-4.2.3.GA (build: SVNTag=JBoss_4_2_3_GA date=200807181439)/JBossWeb- 2.0 Set-Cookie: JSESSIONID=F4EF264027A06BC0A34849F7E2683BFE; Path=/ Location: http://localhost:8009/test Content-Length: 0 Connection: close Content-Type: text/html;charset=ISO-8859-1 Connection closed by foreign host.