Count the number of occurrences of character c in a string in Java

//from  w w  w.j a va 2 s  . c o  m
public class Main {
  public static int countChar(String str, char c) {
    int start = -1;
    int count = 0;
    while (true) {
      if ((start = str.indexOf(c, start + 1)) == -1)
        return (count);
      count++;
    }
  }
  public static void main(String[] argv) {
    System.out.println(countChar("java2s.com",'a'));
  }
}