When starting a J2EE server from Eclipse, make sure that the J2EE server is in a stopped state.

You cannot operate a J2EE server started with tools other than Eclipse from Eclipse. To operate the J2EE application in Eclipse, start the J2EE server with Eclipse.

If a J2EE application with the same name and same format is already imported with a tool other than Eclipse, the J2EE application will be redeployed when deploying the project on the J2EE server with Eclipse. If the already imported J2EE application is deployed in the packaged archive format, the J2EE application will be redeployed. Also, if the already imported J2EE application is deployed in the exploded archive format, the J2EE application will be reloaded. In such a case, if the configuration of the J2EE application is different, the redeploy operation cannot be executed properly. If the redeploy operation cannot be executed, undeploy the J2EE application once in Eclipse, and then redeploy the J2EE application.