collection和collections的区别

import java.util.ArrayList;   
import java.util.Collections;   
import java.util.List;   
  
public class TestCollections {   
       
    public static void main(String args[]) {   
        //注意List是实现Collection接口的   
        List list = new ArrayList();   
        double array[] = { 112, 111, 23, 456, 231 };   
        for (int i = 0; i < array.length; i++) {   
            list.add(new Double(array[i]));   
        }   
        Collections.sort(list);   
        for (int i = 0; i < array.length; i++) {   
            System.out.println(list.get(i));   
        }   
        // 结果：23.0 111.0 112.0 231.0 456.0   
    }   
}