Can anyone tell us what the ! means? "java.io.FileNotFoundException: JAR entry WEB-INF/lib/antlr-runtime-3.5.2.jar!/ not found"
<p>I'm trying to run tapestry atmosphere to write a chat application for a school project. During this I came to an error even my professors don't understand.</p>

<blockquote>
  <p>java.io.FileNotFoundException: JAR entry WEB-INF/lib/antlr-runtime-3.5.2.jar!/ not found</p>
</blockquote>

<p>Nobody know what the "!" stands for. If anyone would know Please let all of us know so tat this error can be thought to new students in the future and present. </p>

<p>this is being done on the demo framework from UkLance : tapestry-atmosphere
<a href="https://github.com/uklance/tapestry-atmosphere" rel="nofollow">https://github.com/uklance/tapestry-atmosphere</a></p>

<p>Below is the error log from (intellij)</p>

<hr>

<blockquote>2016-10-27 10:26:26.980:WARN:oejw.WebAppContext:Scanner-1: Failed startup of context o.e.j.w.WebAppContext@71a39e83{/tapestry-atmosphere-demo,jar:file:///C:("locationToRoot")/tapestry-atmosphere-master/tapestry-atmosphere-demo/target/tapestry-atmosphere-demo.war!/,null}{C:\("locationToRoot")\tapestry-atmosphere-master\tapestry-atmosphere-demo\target\tapestry-atmosphere-demo.war}
java.io.FileNotFoundException: JAR entry WEB-INF/lib/antlr-runtime-3.5.2.jar!/ not found in C:/("locationToRoot")\tapestry-atmosphere-master\tapestry-atmosphere-demo\target\tapestry-atmosphere-demo.war
    at sun.net.www.protocol.jar.JarURLConnection.connect(JarURLConnection.java:142)
    at sun.net.www.protocol.jar.JarURLConnection.getJarFile(JarURLConnection.java:89)
    at org.eclipse.jetty.webapp.MetaInfConfiguration.getTlds(MetaInfConfiguration.java:409)
    at org.eclipse.jetty.webapp.MetaInfConfiguration.scanForTlds(MetaInfConfiguration.java:326)
    at org.eclipse.jetty.webapp.MetaInfConfiguration.scanJars(MetaInfConfiguration.java:143)
    at org.eclipse.jetty.webapp.MetaInfConfiguration.preConfigure(MetaInfConfiguration.java:94)
    at org.eclipse.jetty.webapp.WebAppContext.preConfigure(WebAppContext.java:483)
    at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:519)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:41)
    at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:188)
    at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:499)
    at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:147)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:180)
    at org.eclipse.jetty.deploy.providers.WebAppProvider.fileAdded(WebAppProvider.java:458)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:64)
    at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:610)
    at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:529)
    at org.eclipse.jetty.util.Scanner.scan(Scanner.java:392)
    at org.eclipse.jetty.util.Scanner$1.run(Scanner.java:329)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)
[2016-10-27 10:26:27,252] Artifact tapestry-atmosphere-demo:war: Artifact is deployed successfully
[2016-10-27 10:26:27,252] Artifact tapestry-atmosphere-demo:war: Deploy took 2,079 milliseconds
Disconnected from the target VM, address: '127.0.0.1:57612', transport: 'socket'
</blockquote>

<p>Thank you for taking your time to read/think about this question.</p>