Class Task
public class Task
{
  // Methods
  public static boolean cancel(int id);
  public static int schedule(Runnable runnable);
  public static int schedule(Runnable runnable, long when);
  public static int schedule(Runnable runnable, long when,
        boolean lightweight);
}
This class schedules and manages the execution of runnable objects in the global task manager. 
public static boolean cancel(int id);
Cancels a pending runnable object. 
Return Value: 
Returns true if the runnable object was cancelled successfully; returns false if the task was already run or had never been scheduled. 
| Parameter | Description | 
| id | An integer that identifies the task. | 
public static int schedule(Runnable runnable);
Schedules a runnable object to run immediately in the global task manager as a lightweight task. 
Return Value: 
Returns a non-zero integer that identifies the task. 
| Parameter | Description | 
| runnable | The object scheduled to run. | 
public static int schedule(Runnable runnable, long when);
Schedules a runnable object to run in the global task manager at the specified time as a lightweight task. 
Return Value: 
Returns a non-zero integer that identifies the task. 
| Parameter | Description | 
| runnable | The object that is run. | 
| when | The time at which the object is run. | 
public static int schedule(Runnable runnable, long when,
        boolean lightweight);
Schedules a runnable object to run in the global task manager at the specified time and optionally as a lightweight task or not. 
Return Value: 
Returns a non-zero integer that identifies the task. 
| Parameter | Description | 
| runnable | The object that runs. | 
| when | The time at which the object runs. | 
| lightweight | Set to true to run the task as a lightweight task; false, otherwise. |