public static void main(String[] ar) { String str = " ,,,124,5,5, "; System.out.println(str.contains("123")); List<Integer> list = new ArrayList<>(); list.add(1); list.add(2); list.add(3); list.add(4); list.add(5); list.add(3,31); System.out.println(list); } [1, 2, 3, 31, 4, 5]
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