The Swing Application Framework simplifies the handling of resources in applications and makes it possible for more things to be stored in resource bundles.
A typical Swing Application Framework application has resource bundles at both the application level and the class level. The class-level resource bundles have the same names as their corresponding .java classes except that they contain the .properties extension. All of these bundles are encapsulated by a ResourceMap object.
You can edit some standard application level resources (such as application name) in the Project Properties dialog box. Any application-level resources not included in the Project Properties dialog box (such as resources that you define yourself) can be edited in the the .properties file that corresponds with the name of the main application class.
You can open the Project Properties dialog box by right-clicking the project's node and choosing Properties. Application properties appear in the Application panel and the Desktop Application panel.
When you start an application from the Java Desktop Application project template, by default your code is generated with the Swing Application Framework's conventions for managing resources, such as UI text. The values of component properties that you set are stored as resources as well.
Notes:
You can read more about resource management in the Swing Application Framework's API documentation. Choose Help > Javadoc References > org.jdesktop.application (Swing Application Framework [JSR-296]).