int[] arr = { 123, 129, 1928, 918273645, 12345, 123, 543, 543, 123, 123 };
int size = arr.length;
        
Scanner in = new Scanner(System.in);

for (int i = 0; i < size; i++) {
    for (int j = i; j < size; j++) {
        if (i == j) {
            continue;
        }
        if (arr[i] == arr[j]) {
            System.out.println("Duplicate found of " + i + " at " + j);
            System.out.print("Input replacement: ");
            int replacement = in.nextInt();
            boolean duplicate = true;
            do {
                try {
                    arr[j] = replacement;
                    for (int k = 0; k < j; k++) {
                        if (arr[j] == arr[k]) {
                            System.out.println("You just input at " + j + " the same value as  " + k);
                            throw new Exception();
                        }
                    }
                    duplicate = false;
                } catch (Exception e) {
                    System.out.println("Please enter another value: ");
                    replacement = in.nextInt();
                }
            } while (duplicate);
        }
    }
}