Upgrading gwt from 2.1.1 to 2.8.0: ServiceConfigurationError: org.apache.juli.logging.Log: Provider org.eclipse.jetty.apache.jsp.JuliLog not a subtype

Question

After upgrading gwt from version 2.1.1 to 2.8.0, I got the error message

2017-04-20 12:59:19.551:WARN:oejuc.AbstractLifeCycle:main: FAILED c.g.g.d.s.j.WebAppContextWithReload@341fbaf1{/,file:/C:/Users/xxx/.IntelliJIdea2017.1/system/gwt/xxx.97baa614/xxx.fdf824a8/run/www/,STARTING}{C:\Users\xxx\.IntelliJIdea2017.1\system\gwt\xxx.97baa614\xx.fdf824a8\run\www}: java.util.ServiceConfigurationError: org.apache.juli.logging.Log: Provider org.eclipse.jetty.apache.jsp.JuliLog not a subtype
java.util.ServiceConfigurationError: org.apache.juli.logging.Log: Provider org.eclipse.jetty.apache.jsp.JuliLog not a subtype

I found some other posts with similar messages, like this or this, but the situation seems to be different: I do not use Maven or Ant, just pure IntelliJ, I have no reference to any Tomcat library, and I am not aware of any JSP in our application.

I found through debugging that first the class loader com.google.gwt.dev.shell.jetty.Jettylauncher$WebAppContextWithReload$WebAppClassLoaderExtension loads class org.eclipse.jetty.apache.jsp.JuliLog including interface org.apache.juli.logging.Log.

Then, later interface org.apache.juli.logging.Log is loaded by sun.misc.Launcher$AppClassLoader triggered indirectly by

org.eclipse.jetty.webapp.WebAppContext.startContext()

which calls method initialize of an

org.eclipse.jetty.jsp.JettyJspServlet

instance.

I have no idea why a JspServlet needs to be initialized at all, as no JSPs are used in the application, as far as I see, just a few Servlets. And it seems all the classes involved in this conflict are contained in the single jar gwt-dev.jar, so I see no possibility to influence any class loading behavior via class path settings.

Any idea how I could resolve this?

Answer 1

I am using ant and all information found regarding this error indicated there was 2 versions of Juli Logging in the classpath, but every search came up with only gwt-dev.jar. Production builds worked fine, but dev mode did not which needs gwt-dev.jar.

Part of the build process has the jars copied from a local lib directory to war/WEB-INF/lib to pack into the war. The ant script points to the local lib directory for debugging, not the ones meant for the war file. Despite the war location not being listed in the ant file as a class path, it was still loading it.

Ultimately, gwt-dev.jar was conflicting with the copied version of itself.

Answer 2

I also got this error upgrading from gwt from version 2.4 to 2.8.2.

Jake W's answer helped me.

To solve this, I ran a maven dependency tree on my project to figure out what was referencing jetty's apache-jsp.

To run the dependency tree, in Eclipse I created a new run configuration -> maven build -> with the goals "dependency:tree -Doutput=/dependency/file.txt". Once it's run, the console output will show where it saves the output. It should be the same location that you referenced with the -Doutput option.

Look for something like this in the output file:
- org.eclipse.jetty:apache-jsp:jar:9.2.14.v20151106:compile

And then look up in the tree to see where it's being pulled in from. In my case it came from this:

+- com.google.gwt:gwt-dev:jar:2.8.2:compile   
   +- net.sourceforge.htmlunit:htmlunit:jar:2.19:compile  
   \- org.eclipse.jetty:apache-jsp:jar:9.2.14.v20151106:compile

Once you know where it's coming from, (assuming you're using maven) you can add an exclusion in your pom.xml file for it:

</dependencies>   
        <dependency>
            <groupId>com.google.gwt</groupId>
            <artifactId>gwt-dev</artifactId>
            <version>${gwt.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.eclipse.jetty</groupId>
                    <artifactId>apache-jsp</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
</dependencies>  

This worked for me. Thanks :)

Answer 3

I have just ran into this exception after adding gwt-test-utils:0.53 dependency (with GWT 2.8.1)

Answer 4

I saw this error when I recently upgraded to GWT 2.8.0. Please try to exclude jetty-apache-Jsp related dependencies from your project.

You may see other jetty related issues as well, so please also make sure you are using exactly the same jetty version as GWT 2.8.0 is using.

I'm on mobile at the moment, unable to add more details, but I hope that can be a useful direction to go. Please add your comments if you still see issues, I will then have a look and update the answer when I'm on my laptop.