# Package edu.wpi.first.wpilibj.command

- Class Summary
  Class | Description
  --- | ---
  Command | The Command class is at the very core of the entire command framework.
  CommandGroup | A `CommandGroup` is a list of commands which are executed in sequence.
  ConditionalCommand | A `ConditionalCommand` is a `Command` that starts one of two commands.
  InstantCommand | This command will execute once, then finish immediately afterward.
  PIDCommand | This class defines a `Command` which interacts heavily with a PID loop.
  PIDSubsystem | This class is designed to handle the case where there is a `Subsystem` which uses a single `PIDController` almost constantly (for instance, an elevator which attempts to stay at a constant height).
  PrintCommand | A `PrintCommand` is a command which prints out a string when it is initialized, and then immediately finishes.
  Scheduler | The `Scheduler` is a singleton which holds the top-level running commands.
  StartCommand | A `StartCommand` will call the `start()` method of another command when it is initialized and will finish immediately.
  Subsystem | This class defines a major component of the robot.
  TimedCommand | A `TimedCommand` will wait for a timeout before finishing.
  WaitCommand | A `WaitCommand` will wait for a certain amount of time before finishing.
  WaitForChildren | This command will only finish if whatever `CommandGroup` it is in has no active children.
  WaitUntilCommand | WaitUntilCommand - waits until an absolute game time.

- Exception Summary
  Exception | Description
  --- | ---
  IllegalUseOfCommandException | This exception will be thrown if a command is used illegally.