Print out combinations

Question

hi all
i have got this question
In a file called Combinations.java write a method with the signature:
public void printCombinations(int groupSize, int n)
that prints all the combinations of groupSize numbers taken from the range from 1 to n inclusive, with one group to a line. Groups must appear in numerical order. So, for example, the call printCombinations(3,6) prints the groups:
1 2 3
1 2 4
1 2 5
1 2 6
1 3 4
1 3 5
1 3 6
1 4 5
1 4 6
1 5 6
2 3 4
2 3 5
2 3 6
2 4 5
2 4 6
2 5 6
3 4 5
3 4 6
3 5 6
4 5 6
All the numbers on each line must be separated by a space. You are allowed to assume that printCombinations will only be called with groupSize less than or equal to n and both parameters greater than zero.
i have only managed to write the following codes.
public class Combinations {
     public static void main(String[] args) {
          Combinations q5 = new Combinations();
          q5.printCombinations(3);
     public void printCombinations(int groupsize) {
          printCombinations(groupsize,"  ");
     public void printCombinations(int len1, String  val) {
          if (len1 == 0) {
               System.out.println(" "+ val + " ");
          } else {
               for (int i = 1; i <=6 ; i++) {
                    printCombinations(len1 - 1, val+" "+i);
}output i have is
1 1 1
1 1 2
1 1 3
1 1 4
1 1 5
1 1 6
1 2 1
1 2 2
1 2 3
1 2 4
1 2 5
1 2 6
1 3 1
1 3 2
1 3 3
1 3 4
1 3 5
1 3 6
1 4 1
1 4 2
1 4 3
1 4 4
1 4 5
1 4 6
1 5 1
1 5 2
1 5 3
1 5 4
1 5 5
1 5 6
1 6 1
1 6 2
1 6 3
1 6 4
1 6 5
1 6 6
2 1 1
2 1 2
2 1 3
2 1 4
2 1 5
2 1 6
2 2 1
2 2 2
2 2 3
2 2 4
2 2 5
2 2 6
2 3 1
2 3 2
2 3 3
2 3 4
2 3 5
2 3 6
2 4 1
2 4 2
2 4 3
2 4 4
2 4 5
2 4 6
2 5 1
2 5 2
2 5 3
2 5 4
2 5 5
2 5 6
2 6 1
2 6 2
2 6 3
2 6 4
2 6 5
2 6 6
3 1 1
3 1 2
3 1 3
3 1 4
3 1 5
3 1 6
3 2 1
3 2 2
3 2 3
3 2 4
3 2 5
3 2 6
3 3 1
3 3 2
3 3 3
3 3 4
3 3 5
3 3 6
3 4 1
3 4 2
3 4 3
3 4 4
3 4 5
3 4 6
3 5 1
3 5 2
3 5 3
3 5 4
3 5 5
3 5 6
3 6 1
3 6 2
3 6 3
3 6 4
3 6 5
3 6 6
4 1 1
4 1 2
4 1 3
4 1 4
4 1 5
4 1 6
4 2 1
4 2 2
4 2 3
4 2 4
4 2 5
4 2 6
4 3 1
4 3 2
4 3 3
4 3 4
4 3 5
4 3 6
4 4 1
4 4 2
4 4 3
4 4 4
4 4 5
4 4 6
4 5 1
4 5 2
4 5 3
4 5 4
4 5 5
4 5 6
4 6 1
4 6 2
4 6 3
4 6 4
4 6 5
4 6 6
5 1 1
5 1 2
5 1 3
5 1 4
5 1 5
5 1 6
5 2 1
5 2 2
5 2 3
5 2 4
5 2 5
5 2 6
5 3 1
5 3 2
5 3 3
5 3 4
5 3 5
5 3 6
5 4 1
5 4 2
5 4 3
5 4 4
5 4 5
5 4 6
5 5 1
5 5 2
5 5 3
5 5 4
5 5 5
5 5 6
5 6 1
5 6 2
5 6 3
5 6 4
5 6 5
5 6 6
6 1 1
6 1 2
6 1 3
6 1 4
6 1 5
6 1 6
6 2 1
6 2 2
6 2 3
6 2 4
6 2 5
6 2 6
6 3 1
6 3 2
6 3 3
6 3 4
6 3 5
6 3 6
6 4 1
6 4 2
6 4 3
6 4 4
6 4 5
6 4 6
6 5 1
6 5 2
6 5 3
6 5 4
6 5 5
6 5 6
6 6 1
6 6 2
6 6 3
6 6 4
6 6 5
6 6 6
kindly assist.

Answer 1

try this variation of your program
public class Combinations {
    public static void main(String[] args) {
            Combinations q5 = new Combinations();
            q5.printCombinations(3);
    public void printCombinations(int groupsize) {
            printCombinations(groupsize,"  ");
    public void printCombinations(int len1, String  val) {
            if (len1 == 0) {
                    System.out.println(" "+ val + " ");
            } else {
                    for (int i = 1; i <=6 ; i++) {
                        if(isValidCondidate(val, i)) {
                            printCombinations(len1 - 1, val+" "+i);
    private boolean isValidCondidate(String val, int candidate) {
        String[] splitter = val.split(" ");
        for(int i=0; i < splitter.length ;i ++ ) {
            String string = splitter;
if(!"".equals(string) && Integer.parseInt(string) >=candidate) {
return false;
return true;