Review

class StopWatch {
    /**
     * <p>
     * Get the time on the stopwatch.
     * </p>
     * 
     * <p>
     * This is either the time between the start and the moment this method is called, or the amount of time between
     * start and stop.
     * </p>
     * 
     * @return the time in milliseconds
     */
    public long getTime() {
        if (this.runningState == STATE_STOPPED || this.runningState == STATE_SUSPENDED) {
            return this.stopTime - this.startTime;
        } else if (this.runningState == STATE_UNSTARTED) {
            return 0;
        } else if (this.runningState == STATE_RUNNING) {
            return System.currentTimeMillis() - this.startTime;
        }
        throw new RuntimeException("Illegal running state has occured. ");
    }

}