事实证明，当您将一些GWT项目调试为Web应用程序时，Eclipse不会将模块名称（即gwt.xml文件）附加到参数列表中。我尝试手动添加它，但忘记添加包含gwt.xml文件的完整包名称。该模块应该被称为com.company.project.Project.gwt.xml，而不仅仅是Project.gwt.xml。

After importing a Maven GWT project into Eclipse the debugger doesn't work, complaining that it's

Unable to find ProjectName.gwt.xml on your classpath

How do you fix this error?

It turns out that when you debug some GWT project as Web Applications, Eclipse does not append the module name (i.e. the gwt.xml file) to the list of arguments. I tried adding it manually, but forgot to add the complete package name that houses the gwt.xml file. The module should have been referred to as com.company.project.Project.gwt.xml, not just Project.gwt.xml.