When you choose Run > Run As > RWT Application to launch your entry point, you are running your application using a generic RWT Application launch configuration that derives most of the launch parameters from your Java project and your workbench preferences. In some cases, you will want to override the derived parameters or specify additional arguments.
To create an RWT Application launch configuration from scratch or alter an existing one, select Run > Run Configurations... or Run > Debug Configurations... from the workbench menu bar. This opens a dialog that lets you create, modify, and delete launch configurations of different types. To create a new RWT Application launch configuration, select RWT Application in the left hand list of launch configuration types, and press the New button in the toolbar. The tabs on the right hand side allow you control specific aspects of the launch.
On the Main tab you can control the following aspects of the launch:
org.eclipse.rwt.lifecycle.IEntryPoint
interface in the class name field.
For an explanation of the other tabs see the topic Creating a Java application launch configuration
When an RWT Application launch configuration is launched, it first terminates any possibly running launch that shares the same launch configuration.