First, the application code needs to be adapted in order to communicate with the external IBM Worklight server. Refer to the IBM Worklight Developer's Reference Guide on Transporting Apps and Adapters to Test and Production Environments for the necessary code changes to transfer apps and adapters to a test or production environment.
As you make more changes to the application code, you will need to rebuild the changes locally and republish to the external server. To rebuild the changes locally, use 'Run As -> Build Environment and Deploy' or 'Run As -> Build All and Deploy.' You may notice errors in the Eclipse console view during the deployment step. These are a result of the fact that IBM Worklight Studio continues to deploy to the built-in server, which may not be able to handle the modified code targeted at the external server. These errors can be ignored.
The newly rebuilt binaries that need to be republished to the external server are contained inside the various .wlapp and .adapter files in the "bin" folder of the IBM Worklight Studio project. Use the procedure in the IBM Worklight Developer's Reference Guide (mentioned above) to deploy the appropriate archive to the external server to test the code changes.
These build and deployment steps can be automated using the Ant tasks provided by IBM Worklight. Refer to the IBM Worklight Developer's Reference Guide on "Ant Tasks for Building and Deploying." To execute the Ant tasks, you can use the command line or launch them from inside IBM Worklight Studio by using Eclipse's Ant support. This can greatly improve the speed of the change-code-and-test cycle.