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");
}
}

Finding the Most Common Character in a String

static int countChars( String str, char searchChar ) {
// Count the number of times searchChar occurs in
// str and return the result.
int i; // A position in the string, str.
char ch; // A character in the string.
int count; // Number of times searchChar has been found in str.
count = 0;
for ( i = 0; i < str.length(); i++ ) {
ch = str.charAt(i); // Get the i-th character in str.
if ( ch == searchChar )
count++;
}
return count;
}

Counting all Non-blank Characters in a String

import java.util.Scanner;

public class Count {

public static void main(String[] args) {

for (int count = 1; count <= 5; count ++) {

System.out.println("Please enter some text: ");
Scanner keyboard = new Scanner(System.in);
String text = keyboard.nextLine();

int HowLong = text.length();
String MinusTrailing = text.trim();
int CMinusTrailing = MinusTrailing.length();

String NB = MinusTrailing;
int countChar = 0;
int limit = NB.length();

for(int i = 0; i < limit; ++i)
{
if(Character.isWhitespace(NB.charAt(i)))
{
++count;
}
}

System.out.println(HowLong);
System.out.println(CMinusTrailing);
System.out.println(countChar );


}

}

}