测量重复数据删除的时间（Dedup.treeSetDedup（数组））似乎总是返回0

Question

我正在尝试衡量所需的时间＆＃34; Dedup＆＃34;一组随机的返回单词。如果我将maxWords设置为1000，它将测量重复一组10个单词所需的时间，并在每次迭代时将其递增10，直到达到1000个单词。时间似乎总是0，即使是1000字。我尝试过所有默认类型的重复数据删除（basicDedup，arrayListDedup等等）。

/*....*/

String[] samples; 
Utils.Sampler sampler = new Utils.Sampler(readFile); //sampler with words to read
Utils.Stopwatch timer = new Utils.Stopwatch(); //Used to measure time
Utils.Output out = new Utils.Output(dedupType + ".csv"); //Makes file with the measurement

for (int i = 10; i <= maxWords; i += 10) {
    int size = i; //Words to read for the iteration
    samples = sampler.get(size); //Array containing the words for the iteration

    long time = 0;
    timer.start();
    Dedup.treeSetDedup(samples);
    time = timer.elapsedTime();

    out.addMeasurement(size, time);

}


/*....*/

public static class Stopwatch {
   private final ThreadMXBean timer;
   private long start;

   public Stopwatch(){
       timer = ManagementFactory.getThreadMXBean();
       start();
   }

   /**
    * Start the timer
    */
   public void start(){start = timer.getCurrentThreadCpuTime();}

   /** 
    * Returns the time in nanoseconds since the last call <tt>start()</tt>.
    */
   public long elapsedTime() {
       long now = timer.getCurrentThreadCpuTime();
       return now-start;
   }

   /**
    * Runs the runnable object <tt>r</tt>, and returns the elapsed time
    * measured in nanoseconds.
    */
   public static long elapsedTime(Runnable runnable){
        long start = System.nanoTime();
        runnable.run();
        long stop = System.nanoTime();
        return stop-start;
   }

   /**
    * Calls the given function with the given argument, 
    * and returns the elapsed time measured in nanoseconds.
    */
   public static <T,R> long elapsedTime(Function<T,R> fu, T args){return elapsedTime(() -> fu.apply(args));}

}