Publishing involves copying files such as application, resource files, and deployment descriptor files to the correct location for the server to find and use them. You can choose whether you want to publish your application on the server or run your application within the development environment without copying the application into the directories of the server.
The Run applications directly from the workspace publishing option requests the server to run your application from the workspace.
This publishing option should publish faster when an application contains a single root, as opposed to containing multiple roots. The workbench might require additional processing time to publish an application with multiple roots. To determine whether the structure of your application contains a single or multiple roots, use the Project Structure Validator. For details, see Creating and configuring Java EE projects using wizards.