Make a Distribution

Write a function which takes as input a string that consists only of the digits from 0 to 9 and outputs a distribution (like a grade distribution) showing how many times each digit appears in the string. Specifically, the following main

public static void main(String args[]){
    String s = "01223334444566";
    Distribution.doDistribution(s);
  }
}

should produce the following output:

0:*
1:*
2:**
3:***
4:****
5:*
6:**
7:
8:
9:

We have an outer look that iterates over the numbers (chars) 0 to 9 and then we count how many times each one has occurred. Note that while the numbers in the example are in order, the instructions do not make that claim. A good programmer should realize that if the number are, in fact, always in order that we could re-write this program to use only one loop.

public class Distribution{
  public static void doDistribution(String s){
    for (char c = '0'; c <= '9' ; c++){
      int index = 0;
      int count = 0;
      while ((index = s.indexOf(c,index)) != -1){
        count++;
        index++;
      }
      System.out.print(c + ":");
      for (;count > 0; count--){
        System.out.print("*");
      }
      System.out.println();
    }
  }
  
  public static void main(String args[]){
    String s = "01223334444566";
    Distribution.doDistribution(s);
  }
}