多线程 读取List

import  java.util.ArrayList;
import  java.util.List;
import  org.apache.commons.lang3.ArrayUtils;

public  class  Test_4 {
    /**
     * 多线程处理list
     *
     * @param data  数据list
     * @param threadNum  线程数
     */
    public  synchronized  void  handleList(List data,  int  threadNum) {
        int  length = data.size();
        int  tl = length % threadNum ==  0  ? length / threadNum : (length
                / threadNum +  1 );

        for  ( int  i =  0 ; i < threadNum; i++) {
            int  end = (i +  1 ) * tl;
            HandleThread thread =  new  HandleThread( "线程["  + (i +  1 ) +  "] " ,  data, i * tl, end > length ? length : end);
            thread.start();
        }
    }

    class  HandleThread  extends  Thread {
        private  String threadName;
        private  List data;
        private  int  start;
        private  int  end;

        public  HandleThread(String threadName, List data,  int  start,  int  end) {
            this .threadName = threadName;
            this .data = data;
            this .start = start;
            this .end = end;
        }

        public  void  run() {
            // TODO 这里处理数据
            data.subList(start, end).add( "^&*" );
            System.out.println(threadName)
        }

    }

    public  static  void  main(String[] args) {
        Test_4 test =  new  Test_4();
        // 准备数据
        List data =  new  ArrayList();
        for  ( int  i =  0 ; i <  5000 ; i++) {
            data.add( "item"  + i);
        }
        test.handleList(data,  5 );
        System.out.println(ArrayUtils.toString(data));
    }
}