Java数组、list的转化合并

昨天偶换了一个小方法来实现Java数组、List的转化、合并，并在新数组的第一位置入自己想要或已定的数据变量/对象，代码如下：

    //preCondition
    List list1 = new ArrayList();
    List list2 = new ArrayList();
    list1.add("test1");
    list1.add("test2");
    list2.add(1);
    list2.add(2);
    String temp = "TEMP";
    
    //first:get arrays from list
    Object[] array1 = list1.toArray();
    Object[] array2 = list2.toArray();
    
    //second:get new array that length is list1.size+list2.size 
    Object[] obj = Arrays.copyOf(array1, list1.size()+list2.size()+1);
    for (int j=0; j<=array1.length; j++)
      obj[j] = j==0?temp:array1[j-1];//add temp into obj[0]
    
    //third:add array2's data into obj[]
    for(int i=0; i<array2.length; i++)
      obj[obj.length-i-1] = array2[array2.length-i-1];