Question

What do I need to do to set up a working run configuration for a GWT project using Errai, in IntelliJ IDEA 11 Community Edition (which does not include the GWT plugin)?

I have found instructions for running a GWT project in IntelliJ Community Edition and instructions for working with GWT, CDI and Errai in Eclipse, but when I put these together the run configuration fails to load my app. What configuration is needed?

Answer 1

To get a GWT/Errai project running from IntelliJ 11 Community Edition, go through the following steps:

Add GWT, Errai and your project source directory to the classpath

• Go to File > Project Structure and under Project Settings, select Modules. Select the Dependencies tab.
• You can click the yellow plus button and select ‘Jars or dependencies’ to add dependencies. In this way, add gwt-dev.jar and gwt-user.jar (from the GWT SDK) and a directory containing all your Errai jars (ie: errai-marshalling-(version).jar, errai-data-binding-(version).jar). Make sure the version of these jars matches your Maven (or other build tool) dependencies.

• In the same way, add your project’s src directory. It may come up as ’empty library’ but don’t delete it. Open your project’s .iml file and find the lines referencing your /src and/or /src/main/java directories. If they are under the SOURCES element, move them to sit under CLASSES instead, so you have something like the following. Thanks goes to Stack Overflow user Vic for this hack, contributed to this post.

  <library>
    <CLASSES>
      <root url="file://$MODULE_DIR$/src" />
      <root url="file://$MODULE_DIR$/src/main/java" />
      <root url="file://$MODULE_DIR$/src/main/webapp/WEB-INF/classes" />
    </CLASSES>
    <JAVADOC />
    <SOURCES />
  </library>
  

Create a run configuration

• Create a new Application run configuration (Run > Edit Configurations > + > Application).
• For the Main class, put ‘com.google.gwt.dev.DevMode’.
• Select your project in the ‘Use classpath of module’ menu, if it’s not already selected.

• Add Program arguments equivalent to the following, substituting your project’s parameters. For a description of all the valid arguments, run the configuration with none and check the output.

  -noserver -server org.jboss.errai.cdi.server.gwt.JettyLauncher -war /path/to/project/exploded/war/dir -logLevel INFO -startupUrl App.html project.module.App
  

• Run the configuration and click Launch Default Browser in the GWT Development Mode window. Hopefully, your app will now load.

Troubleshooting

• If you get exceptions, make sure you check the output in the App tab in the GWT Development Mode window, as the output here is not necessarily reflected in the browser or IntelliJ’s log and can be key to diagnosing problems.
• If you get the exception ‘java.lang.RuntimeException: Deferred binding failed for ‘org.jboss.errai.ioc.client.Bootstrapper’ (did you forget to inherit a required module?)’, check under the App tab. You’ve likely forgotten to inherit a GWT module; the output will reveal which one.
• If you get marshalling errors, check that your ErraiApp.properties lists all serializable types, and that main and test copies of this file match.