java 数组 操作

public ArrayList zuhe(){
		
		double []aa = {1.0,2.0,3.0,4.0,5.0,6.0};
		double []bb = {1.0,2.0,3.0,7.0,5.0,8.0};
		String []sa = {"a","b","c00"};
		String []sb = {"a","b","c00"};
		//ArrayList<Double> arryaa = new ArrayList<Double>(Arrays.asList(aa));
		ArrayList<String> arryaa = new ArrayList<String>(Arrays.asList(sa));
		ArrayList<String> arrybb = new ArrayList<String>(Arrays.asList(sb));
		Set<String> set = new HashSet<String>();
		set.addAll(arrybb);
		set.addAll(arryaa);
		arryaa.clear();
		arryaa.addAll(set);
		return arryaa;
		
	}

ArrayList<String> tt = aa.zuhe();
		String s ="";
		for(String  n:tt){
			s+=n;
			System.out.println(s);
		}