There is a new plugin
a fresh start that correctly support multi-module projects, it is not version-bounded with GWT, support multiples
GWT versions and other fixes, improvements and best practices. This plugin is now considered the legacy GWT
GWT maven plugin) and the new one is considered the new generation GWT maven
GWT maven plugin). The legacy maven plugin is still supported but it is strongly
encouraged to use the new one for new projects.
Another aspect of gwt-maven-plugin to be familiar with it can help you configure the embedded Servlet container GWT uses in DevMode. The standard src/main/webapp webapp folder is used by gwt-maven-plugin to run the dev mode server (Jetty).
The Google Plugin for Eclipse automatically handles launching DevMode with a simple right click on your module gwt.xml file "run as > web application".
Using command line
You can use mvn gwt:run to launch DevMode from command line. In such case, the plugin will compile your classes and prepare the exploded webapp structure. DevMode is then launched on your webapp.