当我打印出arraylist的索引时如何删除最后一个逗号

我会在一开始打印逗号，像这样-

boolean first = true;for(String x: list1){    for(String y: list2){        if(x.equalsIgnoreCase(y)){if (first) {    first = false;} else {    System.out.print(", "); // <-- or " ," if you prefer.}System.out.print(list1.indexOf(x));        }    }}