A computer system has a runtime environment (e.g. Java) and a deployment system (e.g. a Spring framework layer) arranged to deploy an application into the runtime environment. The application comprises bundles (e.g. OSGi bundles or JSR modules) each with manifest metadata defining dependencies for the respective bundle. A deployment management unit refers to one or more personality specific deployers to determine which of the bundles have a specific personality from a predetermined set of personality types. The personality specific deployers transform the respective personality-specific bundles by inserting one or more additional dependencies into the metadata of the bundle according to their personality type. The deployment management unit applies one or more operations to all of the plurality of bundles, including installing each of the bundles ready for deployment and deploys those bundles not having a specific personality type. The personality specific deployers deploy the personality-specific bundles according to their respective personality types.