You may want to be clearer about your question. Do you want to develop a Java application (using Swing) and able to run Activiti engine?
A few tips to do that:
1. Make sure your activiti.cfg.xml is in your classpath
2. In your main class, you can initiate all the services needed as follow:
private void init() {
processEngine = ProcessEngines.getDefaultProcessEngine();
runtimeService = processEngine.getRuntimeService();
repositoryService = processEngine.getRepositoryService();
taskService = processEngine.getTaskService();
managementService = processEngine.getManagementService();
identityService = processEngine.getIdentityService();
historyService = processEngine.getHistoryService();
formService = processEngine.getFormService();
}
3. You can start using all services (look up activiti APIs) for your needs.
Good luck