javax.servlet.UnavailableException: No class in holder on deployed application with jsp

Question

I'm having some issues in achieving the following:

I want my backend to return my index.html page on some defined paths, since it is an angular application.

Inside my web.xml I've written:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

  <!--my servlets-->

  <!--HTML5-->
    <servlet>
        <servlet-name>html5Servlet</servlet-name>
        <jsp-file>/index.html</jsp-file>
    </servlet>
    <servlet-mapping>
        <servlet-name>html5Servlet</servlet-name>
        <url-pattern>/</url-pattern>
        <url-pattern>/home</url-pattern>
        <url-pattern>/wp-users</url-pattern>
        <url-pattern>/wp-groups</url-pattern>
    </servlet-mapping>
    <!--HTML5-->

    <security-constraint>
        <web-resource-collection>
            <web-resource-name>all</web-resource-name>
            <url-pattern>/*</url-pattern>
        </web-resource-collection>
        <user-data-constraint>
            <transport-guarantee>CONFIDENTIAL</transport-guarantee>
        </user-data-constraint>
    </security-constraint>

</web-app>

The application works fine in local, however I get the following error on the deployed application while calling my servlets:

javax.servlet.ServletContext log: unavailable
javax.servlet.UnavailableException: No class in holder html5Servlet@830ae0fb==null,jsp=/index.html,order=-1,inst=false
    at org.eclipse.jetty.servlet.BaseHolder.doStart(BaseHolder.java:88)
    at org.eclipse.jetty.servlet.ServletHolder.doStart(ServletHolder.java:363)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:891)
    at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:349)
    at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1406)
    at com.google.apphosting.runtime.jetty9.AppEngineWebAppContext.startWebapp(AppEngineWebAppContext.java:159)
    at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1368)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:778)
    at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:262)
    at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:522)
    at com.google.apphosting.runtime.jetty9.AppEngineWebAppContext.doStart(AppEngineWebAppContext.java:116)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at com.google.apphosting.runtime.jetty9.AppVersionHandlerMap.createHandler(AppVersionHandlerMap.java:244)
    at com.google.apphosting.runtime.jetty9.AppVersionHandlerMap.getHandler(AppVersionHandlerMap.java:182)
    at com.google.apphosting.runtime.jetty9.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:109)
    at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchServletRequest(JavaRuntime.java:693)
    at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchRequest(JavaRuntime.java:655)
    at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:625)
    at com.google.apphosting.runtime.JavaRuntime$NullSandboxRequestRunnable.run(JavaRuntime.java:819)
    at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:274)
    at java.lang.Thread.run(Thread.java:745)

I don't understand while it's missing the class. I've also tried with a jsp file instead of the html one, but it doesn't work. Anyone got any clue ?

Answer 1

*.html is not a recognized servlet <url-pattern> for JSP.

Switch to index.jsp and the JettyJspServlet should start to recognize it as a JSP file.