In playing with the JBoss Central demo applications and with the quickstarts several of these overlap in name. If you have deployed the war files via JBDS into the deployments directory, and then use the quickstarts the API will deploy over the existing application without any issue. It appears on a server restart however it remembers the .war file that is in the deployments directory, and the one deployed via API in the quickstarts. The war file ends up with a deployed failed marker file, but no indication about what is going on is in the console log or in the failed file. Better error reporting would be nice for naming collisions in deployment.