Reloading web application (Enter) fails due to java.lang.ClassNotFoundException error #6977

malvarezdiaz · 2021-10-11T07:40:40Z

Reloading a web application executed with maven-jetty-plugin 9.4.43.v20210629, 9.4.44.v20210927 or 11.0.6 (at least) is failing when executing with apache maven 3.8.2 or 3.8.3, but it worked fine with maven 3.8.1.

Error is different with maven-jetty-plugin 9.x vs 11.x ,but in both cases, the base error is due to java.lang.ClassNotFoundException error (different classes in each case, but classes which can be correctly loaded with starting the web context the first time). Error occurs when ENTER (default key for web context restart) is typed.

NOTE: I don't know if it could be related to #5796. In our case, this happens with a basic web application (using only servlets in case of 9.x version, and using JAX-RS in case of 11.x version).

olamy · 2021-10-11T07:46:44Z

any sample project to reproduce?

malvarezdiaz · 2021-10-11T09:35:28Z

I have attached a simple Apache Maven project with two submodules presenting the fail in a very simple scenario:

Subsytem test-project-util defines a class extending HttpServlet
Subsystem test-project-service defines a class HelloServlet extending the class in the test-project-util subsystem

NOTE: In the jax-rs project, error is different, but probably the cause is the same.

Steps to reproduce the issue:

unzip test-project.zip file
cd test-project
mvn install
cd test-project-service
mvn jetty:run
ENTER (to reload application)
After this, the following exception is raised

[INFO] restarting o.e.j.m.p.JettyWebAppContext@55fee662{WS Test Service,/test-project-service,file:///D://test-project/test-project-service/src/main/webapp/,AVAILABLE}{file:///D:/test-project/test-project-service/src/main/webapp/}
[INFO] Stopped o.e.j.m.p.JettyWebAppContext@55fee662{WS Test Service,/test-project-service,file:///D://test-project/test-project-service/src/main/webapp/,STOPPED}{file:///D:/test-project/test-project-service/src/main/webapp/}
[INFO] Webapp source directory = D:\\test-project\test-project-service\src\main\webapp
[INFO] Reload Mechanic: manual
[INFO] nonBlocking:false
[INFO] Classes = D:\\test-project\test-project-service\target\classes
[INFO] Context path = /test-project-service
[INFO] Tmp directory = D:\\test-project\test-project-service\target\tmp
[INFO] Web defaults = org/eclipse/jetty/webapp/webdefault.xml
[INFO] Web overrides =  none
[INFO] web.xml file = file:///D://test-project/test-project-service/src/main/webapp/WEB-INF/web.xml
[INFO] Webapp directory = D:\\test-project\test-project-service\src\main\webapp
[INFO] Scanning elapsed time=12ms
[WARNING] Failed startup of context o.e.j.m.p.JettyWebAppContext@55fee662{WS Test Service,/test-project-service,file:///D://test-project/test-project-service/src/main/webapp/,UNAVAILABLE}{file:///D://test-project/test-project-service/src/main/webapp/}
java.lang.NoClassDefFoundError: es/testproject/SimpleRestHttpServletTemplate
    at java.lang.ClassLoader.defineClass1 (Native Method)
    at java.lang.ClassLoader.defineClass (ClassLoader.java:1017)
    at java.security.SecureClassLoader.defineClass (SecureClassLoader.java:174)
    at java.net.URLClassLoader.defineClass (URLClassLoader.java:550)
    at java.net.URLClassLoader$1.run (URLClassLoader.java:458)
    at java.net.URLClassLoader$1.run (URLClassLoader.java:452)
    at java.security.AccessController.doPrivileged (Native Method)
    at java.net.URLClassLoader.findClass (URLClassLoader.java:451)
    at org.eclipse.jetty.webapp.WebAppClassLoader.foundClass (WebAppClassLoader.java:642)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadAsResource (WebAppClassLoader.java:615)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass (WebAppClassLoader.java:529)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:522)
    at org.eclipse.jetty.util.Loader.loadClass (Loader.java:64)
    at org.eclipse.jetty.servlet.BaseHolder.doStart (BaseHolder.java:89)
    at org.eclipse.jetty.servlet.ServletHolder.doStart (ServletHolder.java:369)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.servlet.ServletHandler.lambda$initialize$0 (ServletHandler.java:730)
    at java.util.stream.SortedOps$SizedRefSortingSink.end (SortedOps.java:357)
    at java.util.stream.AbstractPipeline.copyInto (AbstractPipeline.java:485)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto (AbstractPipeline.java:474)
    at java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining (StreamSpliterators.java:312)
    at java.util.stream.Streams$ConcatSpliterator.forEachRemaining (Streams.java:735)
    at java.util.stream.ReferencePipeline$Head.forEach (ReferencePipeline.java:658)
    at org.eclipse.jetty.servlet.ServletHandler.initialize (ServletHandler.java:755)
    at org.eclipse.jetty.servlet.ServletContextHandler.startContext (ServletContextHandler.java:379)
    at org.eclipse.jetty.webapp.WebAppContext.startWebapp (WebAppContext.java:1449)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.startWebapp (JettyWebAppContext.java:328)
    at org.eclipse.jetty.webapp.WebAppContext.startContext (WebAppContext.java:1414)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart (ContextHandler.java:910)
    at org.eclipse.jetty.servlet.ServletContextHandler.doStart (ServletContextHandler.java:288)
    at org.eclipse.jetty.webapp.WebAppContext.doStart (WebAppContext.java:524)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.doStart (JettyWebAppContext.java:397)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.maven.plugin.JettyRunMojo.restartWebApp (JettyRunMojo.java:468)
    at org.eclipse.jetty.maven.plugin.ConsoleScanner.restartWebApp (ConsoleScanner.java:114)
    at org.eclipse.jetty.maven.plugin.ConsoleScanner.checkSystemInput (ConsoleScanner.java:78)
    at org.eclipse.jetty.maven.plugin.ConsoleScanner.run (ConsoleScanner.java:46)
Caused by: java.lang.ClassNotFoundException: es.testproject.SimpleRestHttpServletTemplate
    at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass (SelfFirstStrategy.java:50)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass (ClassRealm.java:271)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass (ClassRealm.java:247)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass (ClassRealm.java:239)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass (WebAppClassLoader.java:538)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:522)
    at java.lang.ClassLoader.defineClass1 (Native Method)
    at java.lang.ClassLoader.defineClass (ClassLoader.java:1017)
    at java.security.SecureClassLoader.defineClass (SecureClassLoader.java:174)
    at java.net.URLClassLoader.defineClass (URLClassLoader.java:550)
    at java.net.URLClassLoader$1.run (URLClassLoader.java:458)
    at java.net.URLClassLoader$1.run (URLClassLoader.java:452)
    at java.security.AccessController.doPrivileged (Native Method)
    at java.net.URLClassLoader.findClass (URLClassLoader.java:451)
    at org.eclipse.jetty.webapp.WebAppClassLoader.foundClass (WebAppClassLoader.java:642)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadAsResource (WebAppClassLoader.java:615)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass (WebAppClassLoader.java:529)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:522)
    at org.eclipse.jetty.util.Loader.loadClass (Loader.java:64)
    at org.eclipse.jetty.servlet.BaseHolder.doStart (BaseHolder.java:89)
    at org.eclipse.jetty.servlet.ServletHolder.doStart (ServletHolder.java:369)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.servlet.ServletHandler.lambda$initialize$0 (ServletHandler.java:730)
    at java.util.stream.SortedOps$SizedRefSortingSink.end (SortedOps.java:357)
    at java.util.stream.AbstractPipeline.copyInto (AbstractPipeline.java:485)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto (AbstractPipeline.java:474)
    at java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining (StreamSpliterators.java:312)
    at java.util.stream.Streams$ConcatSpliterator.forEachRemaining (Streams.java:735)
    at java.util.stream.ReferencePipeline$Head.forEach (ReferencePipeline.java:658)
    at org.eclipse.jetty.servlet.ServletHandler.initialize (ServletHandler.java:755)
    at org.eclipse.jetty.servlet.ServletContextHandler.startContext (ServletContextHandler.java:379)
    at org.eclipse.jetty.webapp.WebAppContext.startWebapp (WebAppContext.java:1449)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.startWebapp (JettyWebAppContext.java:328)
    at org.eclipse.jetty.webapp.WebAppContext.startContext (WebAppContext.java:1414)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart (ContextHandler.java:910)
    at org.eclipse.jetty.servlet.ServletContextHandler.doStart (ServletContextHandler.java:288)
    at org.eclipse.jetty.webapp.WebAppContext.doStart (WebAppContext.java:524)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.doStart (JettyWebAppContext.java:397)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:73)
    at org.eclipse.jetty.maven.plugin.JettyRunMojo.restartWebApp (JettyRunMojo.java:468)
    at org.eclipse.jetty.maven.plugin.ConsoleScanner.restartWebApp (ConsoleScanner.java:114)
    at org.eclipse.jetty.maven.plugin.ConsoleScanner.checkSystemInput (ConsoleScanner.java:78)
    at org.eclipse.jetty.maven.plugin.ConsoleScanner.run (ConsoleScanner.java:46)
[INFO] Restart completed at Mon Oct 11 11:32:24 CEST 2021

test-project.zip

olamy · 2021-10-11T10:21:59Z

sounds due to a core maven issue https://issues.apache.org/jira/browse/MNG-7220 see all linked issues...
3.8.1 seems to be the safe option...
but I will look into more details.

malvarezdiaz · 2021-10-11T10:33:40Z

https://issues.apache.org/jira/browse/MNG-7220 seems to affect to 3.8.2. I am not sure if it is fixed in 3.8.3, but problem described in #6977 is also affecting Apache Maven 3.8.3. If you prefer, I could open this task in the Apache Maven core project and close this one.

olamy · 2021-10-11T10:42:46Z

there are many issues in Apache Maven core related to.
But wait I need to confirm it;s due to this. ATM it's just a guess

olamy · 2021-10-11T23:48:01Z

@malvarezdiaz ok definitely related to Maven core issue..
Just looking at your poms.
I would recommend you set the jetty-maven-plugin version in parent pom using pluginManagement section:

        <pluginManagement>
          <plugins>
            <plugin>
              <groupId>org.eclipse.jetty</groupId>
              <artifactId>jetty-maven-plugin</artifactId>
              <version>${jettyMavenPlugin.version}</version>
            </plugin>
          </plugins>
        </pluginManagement>

This will enforce using last 9.4.x version and with such configuration you will be able to simply mvn jetty:run from top directory and this will include compiling every dependant modules (i.e no more install from top then cd into webapp)

malvarezdiaz · 2021-10-12T07:52:48Z

Ok, thanks. I have created a new issue in Maven core: see https://issues.apache.org/jira/browse/MNG-7300 .

olamy closed this as completed Oct 11, 2021

malvarezdiaz changed the title ~~Reloading web application (Ctrl+Enter) fails due to java.lang.ClassNotFoundException error~~ Reloading web application (Enter) fails due to java.lang.ClassNotFoundException error Oct 12, 2021

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Reloading web application (Enter) fails due to java.lang.ClassNotFoundException error #6977

Reloading web application (Enter) fails due to java.lang.ClassNotFoundException error #6977

malvarezdiaz commented Oct 11, 2021 •

edited

olamy commented Oct 11, 2021

malvarezdiaz commented Oct 11, 2021

olamy commented Oct 11, 2021 •

edited

malvarezdiaz commented Oct 11, 2021

olamy commented Oct 11, 2021

olamy commented Oct 11, 2021

malvarezdiaz commented Oct 12, 2021

Reloading web application (Enter) fails due to java.lang.ClassNotFoundException error #6977

Reloading web application (Enter) fails due to java.lang.ClassNotFoundException error #6977

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malvarezdiaz commented Oct 11, 2021 • edited

olamy commented Oct 11, 2021

malvarezdiaz commented Oct 11, 2021

olamy commented Oct 11, 2021 • edited

malvarezdiaz commented Oct 11, 2021

olamy commented Oct 11, 2021

olamy commented Oct 11, 2021

malvarezdiaz commented Oct 12, 2021

malvarezdiaz commented Oct 11, 2021 •

edited

olamy commented Oct 11, 2021 •

edited