Java排序sort

ArrayList<Integer>ans=new ArrayList<>();
		for(int i=0;i<10;i++)
		{
			ans.add((int)(Math.random()*100));
			System.out.print(ans.get(i)+" ");
			
		}
		System.out.println();
		Collections.sort(ans);
		for(int i:ans)
		{
			System.out.print( i+" ");
		}
		System.out.println();
		Collections.reverse(ans);
		for(int i:ans)
		{
			System.out.print( i+" ");
		}