Question

We got a GWT project in Eclipse, that otherwise works.
Now I want to have a script that runs on the server, which pulls the latest version from source control and compiles it on the server and deploys it.
This will save us a lot of manual work and allow us to deploy new version when on a connection with limited bandwidth (since we won’t have to upload the application to the server).

After pulling the latest version of the source code, the script tries to compile the code using the following command:

java -cp "/path/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.5.0.v201211121240-rel-r42/gwt-2.5.0/*:/path/company/projects/pull-compile-deploy/X/X/src:/path/company/projects/pull-compile-deploy/X/X/war/WEB-INF/lib/*" com.google.gwt.dev.Compiler nl.company.projects.X

Compiling module nl.company.projects.X
   Finding entry point classes
      [ERROR] Unable to find type 'nl.company.projects.X.client.XMain'
         [ERROR] Hint: Previous compiler errors may have made this type unavailable
         [ERROR] Hint: Check the inheritance chain from your module; it may not be inheriting a required module or a module may not be adding its source path entries properly

All source code is in /path/company/projects/pull-compile-deploy/X/X/src and all used .jars (except for the GWT stuff) are in /path/company/projects/pull-compile-deploy/X/X/war/WEB-INF/lib/. Obviously something goes wrong.

Questions: The file /path/company/projects/pull-compile-deploy/X/X/src/nl/company/projects/X/client/XMain.java does exist and should imho be in the classpath?!
Anyone Any idea what might go wrong here?
Is it maybe possible to see in some log exactly the commands that eclipse executes for compilation? I looked at the build.xml that eclipse can export, but it seems that does not contain a target to compile for production.

something else: apperantly GWT expects the X.gwt.xml to be at /path/company/projects/pull-compile-deploy/X/X/src/nl/company/project/X.gwt.xml, whereas eclipse put it in /path/company/projects/pull-compile-deploy/X/X/src/nl/company/project/X/X.gwt.xml (i.e. nested one directory deeper), I fixed this by creating a symbolic link.

Further Edit:
Since one answer focused on how I invoked the compilation tools, I have rewritten that in Ant, see below.
The problem remains of course.

<!-- Compile the source using javac. -->
<target name="compile" depends="init">
    <javac srcdir="src/" destdir="bin/">
        <classpath refid="project.classpath"/>
    </javac>
</target>


<!-- Use the GWT-compiler. -->
<target name="gwt-compile" depends="compile">
    <java failonerror="true" fork="true" classname="com.google.gwt.dev.Compiler">
        <classpath>
            <path refid="project.classpath"/>
            <pathelement location="src/"/>
            <pathelement location="bin/"/>
        </classpath>
        <jvmarg value="-Xmx512M"/>
        <arg value="${module.name}"/>
    </java>
</target>

Anything wrong with the above Ant-script?
module.name = nl.company.projects.X and the path with refid="project.classpath" contains all used libraries aswell as the GWT libraries (gwt-user.jar, gwt-dev.jar and validation-api-1.0.0.GA(-source).jar).

The XMain class inherits nothing (other than from Object) and only implements EntryPoint (which is included in the gwt-user.jar). So I do not think the problem is related to the second hint that the compiler gives.

Any ideas?

Answer 1

GWT requires you to javac your classes, it needs both the *.java and the *.class files.

This has not always been the case, and should change back in the future (see https://code.google.com/p/google-web-toolkit/issues/detail?id=7602 for instance), but for now that’s the state of affair: you need to javac before you can com.google.gwt.dev.Compiler.

javac -cp "/path/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.5.0.v201211121240-rel-r42/gwt-2.5.0/*:/path/company/projects/pull-compile-deploy/X/X/war/WEB-INF/lib/*" -sourcepath /path/company/projects/pull-compile-deploy/X/X/src /path/company/projects/pull-compile-deploy/X/X/src/nl/company/projects/X.java -d /path/company/projects/pull-compile-deploy/X/X/bin

java -cp "/path/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.5.0.v201211121240-rel-r42/gwt-2.5.0/*:/path/company/projects/pull-compile-deploy/X/X/src:/path/company/projects/pull-compile-deploy/X/X/bin:/path/company/projects/pull-compile-deploy/X/X/war/WEB-INF/lib/*" com.google.gwt.dev.Compiler nl.company.projects.X

(please double-check the above commands before use)

EDIT: (in response to your “question” re. the X.gwt.xml): GWT expects the X.gwt.xml at nl/company/projects/X.gwt.xml because that’s what you told it to use: module.name = nl.company.projects.x. If the file is at nl/company/projects/X/X.gt.xml then use nl.company.projects.X.X as the module name. Using a symbolic link here is likely to be the problem: the source path for the module (search for <source at https://developers.google.com/web-toolkit/doc/latest/DevGuideOrganizingProjects#DevGuideModuleXml) will then be nl/company/projects/client and thus won’t include nl/company/projects/X/client where your XMain class lives; it’s this unavailable to the GWT compiler.

---

That said, I totally agree with SSR: use a decent build tool: Ant, Maven, Gradle, Make, whatever, it’ll make your life so much easier. A build tool that manages dependencies (Ant+Ivy, Maven, Gradle) is even better IMO.