GWT apps that inherit the com.google.gwt.logging.Logging module have different default behavior for messages logged using the java.util.logging package. The new default is to log messages at level SEVERE and above to the browser's console. PopupLogHandler and SystemHandler are no longer enabled by default.
<set-property name="gwt.logging.enabled" value="TRUE"/>
<set-property name="gwt.logging.consoleHandler" value="ENABLED"/>
<set-property name="gwt.logging.logLevel" value="INFO"/>