GWT webappcreator creating Maven project: source attachment does not contain source for URLClassPath.class file

Question

I created a Maven2-based GWT application, imported it into Eclipse, and when I debug as a GWT web application, the Eclipse debugging session is suspended using FileNotFoundException. It displays a window saying: The original attachment does not contain a source for the URLClassPath.class file.

I completely destroyed the Eclipse workspace (and the .metadata subdirectory), created / imported an empty project, and the same thing happens. If I run Launch as a GWT Web Application, it works fine (with a few warnings). What do I need to configure this work in debug mode?

Steps to reproduce the problem

1) Create an application

webAppCreator -noant -maven -XnoEclipse -out MyApp com.example.MyApp

2) Import and change settings

• The application is imported into the Eclipse workspace, in the settings for the "Use Google Web Toolkit" checkbox is checked.

• "This project has a WAR directory." The WAR directory is set to src / main / webapp. "Launch and deployment from this directory" is not installed.

3) Debugging as

Now click on the debug toolbar button, select "GWT Web Application" and select target / www as the WAR directory. You should see the same problem. The call stack in the Debug panel contains the following:

MyApp.html [Web Application]
com.google.gwt.dev.DevMode at localhost: 51620 Topic [main] (Suspended (FileNotFoundException exception))
URLClassPath $ JarLoader.getJarFile (URL) string: 644
URLClassPath $ JarLoader.access $ 600 ($ URLClassPath JarLoader, URL): 540
URLClassPath $ JarLoader $ 1.run (): 607
AccessController.doPrivileged (PrivilegedExceptionAction) string: unavailable [native method]
URLClassPath $ JarLoader.ensureOpen () line: 599
URLClassPath $ JarLoader. (URL, URLStreamHandler, HashMap): 583
URLClassPath $ JarLoader $ 3.run (): 810
AccessController.doPrivileged (PrivilegedExceptionAction) string: unavailable [native method]
URLClassPath $ JarLoader.getResource (String, boolean, Set): 806
URLClassPath $ JarLoader.getResource (String, boolean): 765
URLClassPath.getResource (String, boolean): 169
URLClassLoader $ 1.run (): 194
AccessController.doPrivileged (PrivilegedExceptionAction, AccessControlContext): none available [native method]
Launcher $ AppClassLoader (URLClassLoader) .findClass (String) line: 190
Launcher $ AppClassLoader (ClassLoader) .loadClass (String, boolean): 307
Launcher $ AppClassLoader.loadClass (String, boolean): 301
Launcher $ AppClassLoader (ClassLoader) .loadClass (String) line: 248 C: \ Program Files \ Java \ jdk1.6.0_21 \ Bin \ javaw.exe (11.28.2010 15:28:32)

Versions and Plugins

GWT: 2.1.

Eclipse: Helios (3.6).

Maven: 2.2.1.

JRE / JDK: JDK 1.6.0.21.

Google Plugin for Eclipse 3.6 version 1.4.0.v201010280102.

Maven integration for Eclipse (m2eclipse) version 0.10.2.20100623-1649 (this was configured to specify the Maven 2.2.1 environment and DO NOT use the built-in instance of Maven3).

Answer 1

In Eclipse, go to Window -> Preferences -> Java -> Debug and disable all options to pause execution.

Since this error is probably not caused by your application, you really don't need the source for this class (URLClassPath). You can find the Oracle / Sun Java site for sources and tell Eclipse to them if you really want to;)