1. A device for managing an application composed of instructions executable by an execution system, said execution system communicating with an operating system so as to access resources of the device, wherein the device comprises an applications manager, including a storage medium, which can execute at least one received management instruction set, said application manager executing management instructions from said at least one received management instruction set both before running of the application and during running of the application, said at least one management instruction set modifying via functions a state of the device before the running of the application executed by the operating system and/or the execution system and the running of said application, said at least one management instruction set being executed upon a change of state and/or upon an event external to the device, and executed before the launching of the application and during the running of this application, said at least one management instruction set being provided by an external source, wherein said application manager comprises several sets of management instructions originating from several sources of management instructions; a specified management instruction set being assigned to each application.