BubbleSort线程不起作用

我想创建一个将使用BubbleSort方法对数组进行排序的线程，但是我遇到了一些问题。

这是我的BubbleSort类：

package thread;
import java.util.Arrays;

public class BubbleSort implements Runnable {

private int[] array;
private long start, end;

public BubbleSort(int[] array){
    this.array=array;
}

public void sort(){
    int j;
    boolean flag = true;  
    int temp;

    while (flag) {
        flag= false;
        for( j=0;j<array.length-1;j++ ){
            if (array[j]>array[j+1]){
                temp = array[ j ];            
                array[j] = array[ j+1 ];
                array[j+1] = temp;
                flag=true;            
            } 
       } 
    } 
}

@Override
public void run() {
   start = System.currentTimeMillis();
   this.sort();
   end = System.currentTimeMillis();
   System.out.println(end-start);
}

public long getTime(){
    return end - start;
}

@Override
public String toString(){
    return Arrays.toString(array);
}

}

和主要类别：

package multisort;

import thread.BubbleSort;

    public class MultiSort {

    public static void main(String[] args) {
        int[] x = {12,34,53,1,23,532,102,31,12,0,344,123,5422,12341,22,3410,123,342,233,12342,234432,12334};
        BubbleSort bs = new BubbleSort(x);
        Thread bsThread = new Thread(bs);
        bsThread.start();
        System.out.println(bs+"\n"+bs.getTime());
        /*
        bs.sort();
        System.out.println(bs); it works
        */
    }

}

问题是，如果我在run方法中调用sort方法，数组将不会被排序。谁可以帮助我作出回应？