char array to 2d char array with constraints

I need help with sorting elements of the char[] {'A','B','C','D',' ',' '} into a char[6][6] where each row and each column has each of the 6 char[6] elements once. Below is the code I have so far. The problem is that I cannot generate a 2d array that fits this description. If anyone knows how to do this, that would be great!

Example ending array (I need a program that will generate ALL permutations, not just this one.):

ABCD  
 ABCD 
  ABCD
D  ABC
CD  AB
BCD  A

My code:

import java.util.Arrays;
import java.util.Collections;

public class Main {
public static char[] characters = {'A','B','C','D',' ',' '};

public static void main(String[]a){
    char[][] temp = new char[6][];
        temp = getRows(characters);
}

public static char[][] getRows(char[] chars){
    char[][] rows = new char[6][];
    int a = 0;
    for (int i = 0; i < 6; i++) {
        for (int j = 0; j < 6; j++) {
            for (int k = 0; k < 6; k++) {
                for (int l = 0; l < 6; l++) {
                    for (int m = 0; m < 6; m++) {
                        tester:
                        for (int n = 0; n < 6; n++) {
                            char[] temp = {chars[i], chars[j], chars[k], chars[l], chars[m], chars[n]};
                            for (int o = 0; o < 6; o++) {
                                //System.out.println(arrayToString(temp));
                                if (Collections.frequency(Arrays.asList(temp), characters[o]) > 1 || Collections.frequency(Arrays.asList(temp), characters[o]) == 0) {
                                    continue tester;
                                }
                            }
                            if (a + 1 == 6) return rows;
                            System.out.println(arrayToString(temp));
                            rows[a] = temp;
                            a++;

                        }
                    }
                }
            }
        }
    }
    return new char[6][6];
}

public static String arrayToString(char[] objects) {
    String s = "{";
    for (int i = 0; i < objects.length; i++) {
        s += objects[i];
        if (i < objects.length - 1)
            s += ",";
    }
    s += "}";
    return s;
}

}