Note that calling this method from within the run method of a timer task that was invoked by this timer absolutely guarantees that the ongoing task execution is the last task execution that will ever be performed by this timer.

This method may be called repeatedly; the second and subsequent calls have no effect.

Most programs will have no need to call this method. It is designed for use by the rare application that cancels a large number of tasks. Calling this method trades time for space: the runtime of the method may be proportional to n + c log n, where n is the number of tasks in the queue and c is the number of cancelled tasks.

Note that it is permissible to call this method from within a a task scheduled on this timer.
Returns: the number of tasks removed from the queue.
Since: 1.5

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.
Parameters:
- task - task to be scheduled.
- firstTime - First time at which task is to be executed.
- period - time in milliseconds between successive task executions.
Throws:
- IllegalArgumentException - if time.getTime() is negative.
- IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.
Parameters:
- task - task to be scheduled.
- delay - delay in milliseconds before task is to be executed.
- period - time in milliseconds between successive task executions.
Throws:
- IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
- IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

In fixed-rate execution, each execution is scheduled relative to the scheduled execution time of the initial execution. If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up." In the long run, the frequency of execution will be exactly the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-rate execution is appropriate for recurring activities that are sensitive to absolute time, such as ringing a chime every hour on the hour, or running scheduled maintenance every day at a particular time. It is also appropriate for recurring activities where the total time to perform a fixed number of executions is important, such as a countdown timer that ticks once every second for ten seconds. Finally, fixed-rate execution is appropriate for scheduling multiple repeating timer tasks that must remain synchronized with respect to one another.
Parameters:
- task - task to be scheduled.
- firstTime - First time at which task is to be executed.
- period - time in milliseconds between successive task executions.
Throws:
- IllegalArgumentException - if time.getTime() is negative.
- IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

In fixed-rate execution, each execution is scheduled relative to the scheduled execution time of the initial execution. If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up." In the long run, the frequency of execution will be exactly the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-rate execution is appropriate for recurring activities that are sensitive to absolute time, such as ringing a chime every hour on the hour, or running scheduled maintenance every day at a particular time. It is also appropriate for recurring activities where the total time to perform a fixed number of executions is important, such as a countdown timer that ticks once every second for ten seconds. Finally, fixed-rate execution is appropriate for scheduling multiple repeating timer tasks that must remain synchronized with respect to one another.
Parameters:
- task - task to be scheduled.
- delay - delay in milliseconds before task is to be executed.
- period - time in milliseconds between successive task executions.
Throws:
- IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
- IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.