Java Webstart not working offline (NoRouteToHostException/UnknownHostException)

[Mathias Lin]

I want to configure my webstart app/jnlp so that if no internet
connection is available, it would start from cache. *Nevertheless,
when I disconnect from the internet, I always get a
NoRouteToHostException or UnknownHostException exception, despite the
configuration below.*

I've set the offline-allowed and update tags/attributes properly I
think; I cannot find the reason why webstart is still trying to lookup
the host. I definitely do have the app cached from my previous start
when I was connected.


jnlp file:
==========

<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="6.0+" codebase="http://cms.mydomain.com/sync/"
href="myAppSync.jnlp">

<information>
<title>My App Sync</title>
<vendor>My Company</vendor>
<homepage href="http://www.myapp.com/"/>
<description>Sync application for My App</description>
<icon href="ATTico.png"/>

<!-- allow app to run without Internet access -->
<offline-allowed/>

<shortcut online="true">
<desktop/>
<!-- create menu item for this app under the major heading 'My
App' -->
<menu submenu="My App"/>
</shortcut>

</information>

<security>
<all-permissions/>
</security>

<update check="timeout" policy="always" />

<resources>
<java version="1.6*" href="http://java.sun.com/products/autodl/
j2se"/>
<jar href="lib/myAppSync.jar" />
<jar href="lib/apache-mime4j-0.6.jar" />
<jar href="lib/commons-logging-1.1.1.jar" />
<jar href="lib/commons-codec-1.3.jar" />
<jar href="lib/httpclient-4.0.1.jar" />
<jar href="lib/httpcore-4.0.1.jar" />
<jar href="lib/httpmime-4.0.1.jar" />
<jar href="lib/swingx-1.6.jar" />
<jar href="lib/swingx-beaninfo-1.6.jar" />
</resources>

<application-desc main-class="com.myapp.sync.forms.Main"/>

</jnlp>


error log:
==========
java.net.NoRouteToHostException: No route to host: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.<init>(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at
sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown
Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown
Source)
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doRequest(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doGetRequestEX(Unknown Source)
at com.sun.deploy.net.DownloadEngine.isUpdateAvailable(Unknown Source)
at com.sun.deploy.net.DownloadEngine.isUpdateAvailable(Unknown Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(Unknown
Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(Unknown
Source)
at com.sun.deploy.net.DownloadEngine.getResource(Unknown Source)
at com.sun.javaws.LaunchDownload.downloadJarFiles(Unknown Source)
at com.sun.javaws.LaunchDownload.downloadEagerorAll(Unknown Source)
at com.sun.javaws.Launcher.downloadResources(Unknown Source)
at com.sun.javaws.Launcher.prepareLaunchFile(Unknown Source)
at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
at com.sun.javaws.Launcher.launch(Unknown Source)
at com.sun.javaws.Main.launchApp(Unknown Source)
at com.sun.javaws.Main.continueInSecureThread(Unknown Source)
at com.sun.javaws.Main$1.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

or sometimes:

java.net.UnknownHostException: cms.mydomain.com
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.<init>(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at
sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown
Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown
Source)
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doRequest(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doGetRequestEX(Unknown Source)
at com.sun.deploy.net.DownloadEngine.isUpdateAvailable(Unknown Source)
at com.sun.deploy.net.DownloadEngine.isUpdateAvailable(Unknown Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(Unknown
Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(Unknown
Source)
at com.sun.deploy.net.DownloadEngine.getResource(Unknown Source)
at com.sun.javaws.LaunchDownload.downloadJarFiles(Unknown Source)
at com.sun.javaws.LaunchDownload.downloadEagerorAll(Unknown Source)
at com.sun.javaws.Launcher.downloadResources(Unknown Source)
at com.sun.javaws.Launcher.prepareLaunchFile(Unknown Source)
at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
at com.sun.javaws.Launcher.launch(Unknown Source)
at com.sun.javaws.Main.launchApp(Unknown Source)
at com.sun.javaws.Main.continueInSecureThread(Unknown Source)
at com.sun.javaws.Main$1.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

 

[Mathias Lin]

I found that when I call 'javaws -offline myApp.jnlp' (with the -
offline parameter!), webstart won't check online and throw an
exception. But then it would also not check for updates IF I am
actually connected to the internet.
So with -offline, the offline mode works as I want it to, but it
doesn't make much sense to me why it's necessary to add this param.
Why does webstart not simply timeout when it cannot find the host in
the regular mode?