Count letters in a String

/**
*
* @author javadb.com
*/
public class Main {

/**
* This method counts the number of letters in a String
*/
public void countLetters(String str) {

if (str == null)
return;

int counter = 0;

for (int i = 0; i < str.length(); i++) {

if (Character.isLetter(str.charAt(i)))
counter++;
}

System.out.println("The input parameter contained " + counter + " letters.");
}


/**
* @param args the command line arguments
*/
public static void main(String[] args) {
new Main().countLetters("abcde123");
}
}