eclipse help window shows 404

[Martin Pool]

Eclipse in Precise always shows an error when I try to access any builtin help:

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HTTP ERROR 404

Problem accessing /help/index.jsp. Reason:

    ProxyServlet: /help/index.jsp
Powered by Jetty://

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This is like https://bugs.launchpad.net/ubuntu/+source/eclipse/+bug/549904 but a different error.

There is some debug output but no error is obvious to me:

16:24:03.541 [Start Help Server] DEBUG org.mortbay.log - Container Server@132803ba + SelectChannelConnector@127.0.0.1:51975 as connector
16:24:03.575 [Start Help Server] DEBUG org.mortbay.log - filterNameMap=null
16:24:03.575 [Start Help Server] DEBUG org.mortbay.log - pathFilters=null
16:24:03.575 [Start Help Server] DEBUG org.mortbay.log - servletFilterMap=null
16:24:03.575 [Start Help Server] DEBUG org.mortbay.log - servletPathMap={/*=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433}
16:24:03.575 [Start Help Server] DEBUG org.mortbay.log - servletNameMap={org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433}
16:24:03.575 [Start Help Server] DEBUG org.mortbay.log - Container Server@132803ba + org.mortbay.jetty.servlet.Context@215750e4{/help,null} as handler
16:24:03.576 [Start Help Server] DEBUG org.mortbay.log - Container ServletHandler@6b7fb9d5 + org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433 as servlet
16:24:03.576 [Start Help Server] DEBUG org.mortbay.log - Container ServletHandler@6b7fb9d5 + (S=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433,[/*]) as servletMapping
16:24:03.576 [Start Help Server] DEBUG org.mortbay.log - Container SessionHandler@e818616 + ServletHandler@6b7fb9d5 as handler
16:24:03.576 [Start Help Server] DEBUG org.mortbay.log - Container SessionHandler@e818616 + org.mortbay.jetty.servlet.HashSessionManager@598a15ca as sessionManager
16:24:03.576 [Start Help Server] DEBUG org.mortbay.log - Container org.mortbay.jetty.servlet.Context@215750e4{/help,null} + SessionHandler@e818616 as handler
16:24:03.576 [Start Help Server] INFO org.mortbay.log - jetty-6.1.x
16:24:03.585 [Start Help Server] DEBUG org.mortbay.log - Container Server@132803ba + org.mortbay.thread.QueuedThreadPool@684eaf47 as threadpool
16:24:03.586 [Start Help Server] DEBUG org.mortbay.log - started org.mortbay.thread.QueuedThreadPool@684eaf47
16:24:03.596 [Start Help Server] DEBUG org.mortbay.log - Container org.mortbay.jetty.servlet.Context@215750e4{/help,null} + ErrorHandler@6501fa06 as errorHandler
16:24:03.597 [Start Help Server] DEBUG org.mortbay.log - Container Server@132803ba + org.mortbay.jetty.servlet.HashSessionIdManager@77cf08b7 as sessionIdManager
16:24:03.597 [Start Help Server] DEBUG org.mortbay.log - Init SecureRandom.
16:24:03.599 [Start Help Server] DEBUG org.mortbay.log - started org.mortbay.jetty.servlet.HashSessionIdManager@77cf08b7
16:24:03.601 [Start Help Server] DEBUG org.mortbay.log - started org.mortbay.jetty.servlet.HashSessionManager@598a15ca
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - filterNameMap=null
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - pathFilters=null
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - servletFilterMap=null
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - servletPathMap={/*=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433}
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - servletNameMap={org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433}
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - starting ServletHandler@6b7fb9d5
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - started ServletHandler@6b7fb9d5
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - starting SessionHandler@e818616
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - started SessionHandler@e818616
16:24:03.602 [Start Help Server] DEBUG org.mortbay.log - starting org.mortbay.jetty.servlet.Context@215750e4{/help,null}
16:24:03.603 [Start Help Server] DEBUG org.mortbay.log - starting ErrorHandler@6501fa06
16:24:03.603 [Start Help Server] DEBUG org.mortbay.log - started ErrorHandler@6501fa06
16:24:03.605 [Start Help Server] DEBUG org.mortbay.log - started org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433
16:24:03.606 [Start Help Server] DEBUG org.mortbay.log - started org.mortbay.jetty.servlet.Context@215750e4{/help,null}
16:24:03.606 [Start Help Server] DEBUG org.mortbay.log - starting Server@132803ba
16:24:03.613 [Start Help Server] DEBUG org.mortbay.log - started org.mortbay.jetty.nio.SelectChannelConnector$1@55cb5fea
16:24:03.615 [Start Help Server] INFO org.mortbay.log - Started SelectChannelConnector@127.0.0.1:51975
16:24:03.616 [Start Help Server] DEBUG org.mortbay.log - started SelectChannelConnector@127.0.0.1:51975
16:24:03.616 [Start Help Server] DEBUG org.mortbay.log - started Server@132803ba
16:24:03.943 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - REQUEST /help/index.jsp on org.mortbay.jetty.HttpConnection@768e7b84
16:24:03.944 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - sessionManager=org.mortbay.jetty.servlet.HashSessionManager@598a15ca
16:24:03.944 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - session=null
16:24:03.944 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - servlet=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433
16:24:03.944 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - chain=null
16:24:03.944 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - servlet holder=org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet-753974433
16:24:03.959 [148603221@qtp-1749987143-0 - /help/index.jsp] DEBUG org.mortbay.log - RESPONSE /help/index.jsp 404
16:24:04.009 [148603221@qtp-1749987143-0 - /favicon.ico] DEBUG org.mortbay.log - REQUEST /favicon.ico on org.mortbay.jetty.HttpConnection@768e7b84
16:24:04.009 [148603221@qtp-1749987143-0 - /favicon.ico] DEBUG org.mortbay.log - RESPONSE /favicon.ico 200

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: eclipse 3.7.1-1
ProcVersionSignature: Ubuntu 3.2.0-11.19-generic 3.2.1
Uname: Linux 3.2.0-11-generic x86_64
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
Date: Sat Jan 28 16:20:13 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
PackageArchitecture: all
SourcePackage: eclipse
UpgradeStatus: Upgraded to precise on 2011-12-15 (44 days ago)