In order for the interfaces you create to work outside of the IDE, you must include the Swing Layout Extensions library when deploying your applications. This Library contains the various layout-related extensions that the GUI Builder uses at design time and must be on the application's classpath at runtime as well.
NetBeans_installation_folder/ide7/modules/ext/swing-layout-installed_version.jar
To ensure that your GUI application can reference the Swing Layout Extensions library at runtime, the IDE automatically copies the JAR (and any other JAR files on the project's classpath) to the dist/lib folder whenever you build the project. The IDE also adds each of the JAR files to the Class-Path element in the application JAR's manifest.mf file.
To prepare your GUI application for distribution outside of the IDE:
Once you have distributed an archive of your GUI application, your application can be run outside of the IDE from the command line.
To run a standalone GUI application from the command line:
java -jar jar_name.jar
For more information about the Swing layout extension, visit: