GWT Warning “Non-canonical source package”

by Max Rohde,

The Problem

Sometimes you might want to include classes from a package in your gwt module, which are not in a sub-package of the package in which you have defined the Gwt module (MyModule.gwt.xml).

For instance, you might have the following directory structure:




The first natural option would be to define a source dependency in the Gwt module (gwt.xml) as follows:

However, when compiling the module, a "Non-canonical source package" warning is issued. Furthermore, the class in the client package will not be recognized by the Gwt compiler.

The Solution

One clean (but not necessary straightforward) solution is to define a new Gwt module in the client package, and link this in your original module. The directory structure would change to:





The following dependency would have to be added to MyModule.gwt.xml:


GWT Google Group – Source-Source

Categories: java