Array with loops Java -

i want print put elements in array occur twice. if, example, number 2 occurs 3 or 4 times, should not printed. code i've written far below. issue in code loop. example, number 2, since j=i+1 initialization condition, inner loop won't read elements before jth location- since there 2 @ index 6, won't count 2s before it, making required condition true , displaying 2. there way fix this?

public class problem2 {      public static void exactlytwice(int[] x) {         int count, j;         (int = 0; < x.length; i++) {             count = 0;             (j = + 1; j < x.length; j++) {                 if (x[i] == x[j])                     count++;             }             if (count == 1)   system.out.print(x[i] + " ");         }     }      public static void main(string[] args) {         int[] x = new int[15];         x[0] = 2;         x[1] = 2;         x[2] = 2;         x[3] = 13;         x[4] = 44;         x[5] = 44;         x[6] = 2;         x[7] = 63;         x[8] = 63;         x[9] = 90;         x[10] = 1;         x[11] = 2;         x[12] = 150;         x[13] = 150;         x[14] = 180;          exactlytwice(x);     } } 

aside issue wrote, bigger problem see code inefficient. doing loop inside loop here, slow (o(n^2)).

my suggestion keep map of numbers->count, , take ones appear twice in map:

public static void exactlytwice(int[] x) {     map<integer, integer> counter = new hashmap<>();     (int = 0; < x.length; i++) {         if (counter.contains(i)) {            counter.put(i,1);         } else {            counter.put(i,counter.get(i)+1);         }     }      (integer : counter.keyset()) {         if (counter.get(i) == 2) {           system.out.println(i);         }     } }