Random Array Repeating

So I am creating a penny game where the code will randomly choose 5 cells. I set it like so:

    int a = gen.nextInt(5);
    int b = gen.nextInt(5);
    int c = gen.nextInt(5);
    int d = gen.nextInt(5);
    int e = gen.nextInt(5);
    int f = gen.nextInt(5);
    int g = gen.nextInt(5);
    int h = gen.nextInt(5);
    int i = gen.nextInt(5);
    int j = gen.nextInt(5);
    int penny1 = Parray[a][b];
    int penny2 = Parray[c][d];
    int penny3 = Parray[e][f];
    int penny4 = Parray[g][h];
    int penny5 = Parray[i][j];

The problem is that sometimes the random cells are repeated.

How can I make it so a random array cell cannot be repeated or chosen again?