tribute and the task level details. If the task is created and executed in a single command in some program, then, depending on the Boolean values that have been assigned to, or are returned by, the methods setPersistence, setNewTask and setOverwrite, the task may or may not be stored in the database. For example, the persistence property will be in effect only if the method setNewTask is set to "true". 11.2.4.2 Sets of Tasks When a set of tasks is executed from the client, a session is established between the CMS and the device under configuration. Once the task is executed, the session is terminated. If the user wishes to execute, say, 10 tasks over the same device, then rather than closing and reestablishing the session for the next task, the user can reuse the session already established. A combined task is a combination of sub-tasks where each sub-task is defined in some particular protocol. It is useful to create a combined task when a sequence of operations must be carried out on a device, and each operation is carried out by a task. For example, if a user wishes to configure a device with two different tasks, such as to allocate capacity and send a confirmation message to the NOC, then a Device d1=new Device ("localhost", "161") Device d2=new Device ("devicel", "161") Figure 11.6 Code for defining devices. 11 Configuration Management single task can be created with these as sub-tasks. In order to create a multiple task, the tasks to become the sub-tasks must already be created. Device lists are those which have a set of devices, grouped by certain properties. To execute a task over a set of devices, those devices can be specified as a device list and stored. When a task is executed, the task can be associated with a device list, SO that the task is executed over all devices given in the device list. Once the device list is stored, tasks can be associated at the time of execution. Before creating a combined task, the individual tasks must be created. If there already exist individual tasks called t1 and t2