NoClassDefFoundError: javax/servlet/Servlet when running codeserver of GWT 2.8.0

[trohr]

Hi Thomas,

I tried upgrading to GWT 2.8.0 because of some other issue, but I can't seem to be able to get it running. Running code-server exits with error.

[WARNING] java.lang.NoClassDefFoundError: javax/servlet/Servlet
[WARNING] 	at com.google.gwt.dev.codeserver.SourceHandler.<clinit>(SourceHandler.java:63)
[WARNING] 	at com.google.gwt.dev.codeserver.Recompiler.loadModule(Recompiler.java:500)
[WARNING] 	at com.google.gwt.dev.codeserver.Recompiler.initWithoutPrecompile(Recompiler.java:204)
[WARNING] 	at com.google.gwt.dev.codeserver.Outbox.maybePrecompile(Outbox.java:89)
[WARNING] 	at com.google.gwt.dev.codeserver.Outbox.<init>(Outbox.java:61)
[WARNING] 	at com.google.gwt.dev.codeserver.CodeServer.makeOutboxTable(CodeServer.java:191)
[WARNING] 	at com.google.gwt.dev.codeserver.CodeServer.start(CodeServer.java:150)
[WARNING] 	at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:102)
[WARNING] 	at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:55)
[WARNING] Caused by: java.lang.ClassNotFoundException: javax.servlet.Servlet
[WARNING] 	at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
[WARNING] 	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
[WARNING] 	at java.security.AccessController.doPrivileged(Native Method)
[WARNING] 	at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
[WARNING] 	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
[WARNING] 	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
[WARNING] 	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
[WARNING] 	... 9 more

[ERROR] Failed to execute goal net.ltgt.gwt.maven:gwt-maven-plugin:1.0-rc-6:codeserver (default-cli) on project insolvency-client-parent: GWT exited with status 1 -> [Help 1]

I tried adding dependency to your plugin definition, but the output does not change:

        <plugin>
          <groupId>net.ltgt.gwt.maven</groupId>
          <artifactId>gwt-maven-plugin</artifactId>
          <version>1.0-rc-6</version>
          <extensions>true</extensions>
          <configuration>
            <sourceLevel>1.8</sourceLevel>
            <failOnError>true</failOnError>
          </configuration>
          
          <dependencies>
            <dependency>
              <groupId>javax.servlet</groupId>
              <artifactId>javax.servlet-api</artifactId>
              <version>3.1.0</version>
              <scope>runtime</scope>
            </dependency>
          </dependencies>
        </plugin>

Is this a bug or do I make some error?
Thank you.

Sincerely yours
Tomas Rohrbacher

[tbroyer]

gwt:codeserver will use as classpath the dependencies for all the projects matching the classpathScope; these should include gwt-dev and gwt-user which will bring javax.servlet transitively.

It might be that you set javax.servlet with scope provided, which excludes it from the runtime scope (default value for classpathScope). In this case, depending on your project layout, either remove the <scope>provided</scope> or set classpathScope to compile or compile+runtime.

In any case, adding dependencies to the plugin definition won't do anything.

[shauntarves]

I encountered this same problem in a subtlety different way.

My project inherits from a parent pom that has a <dependencyManagement> section which specifies a provided scope for javax.servlet. It was not enough to override the javax.servlet dependency scope to runtime even though my classpathScope was the default (runtime). I had to override the dependency scope to compile in order for the plugin to include it on the classpath.