hi, this is a little example I made in java to count the letters, uppcase and lowercase spaces, digits in a string.
anyway hope you like it, note I am still learning java so there maybe things I can do betters comments are welcome.

Code:
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Scanner;


public class Main {

    //Checks for words not including digits or other symbols
    public static boolean isWord(String S){
        boolean flag;
        char[] chars = S.toCharArray();
        flag = true;
        for(char c : chars){
            if(!Character.isLetter(c)){
                flag = false;
                break;
            }
        }
        return flag;
    }
    public static void main(String[] args) {
        int letters = 0;
        int spaces = 0;
        int numbers = 0;
        int words = 0;
        int upperCase = 0;
        int lowerCase = 0;
        int other = 0;
        int lines = 0;

        if(args.length == 0){
            System.out.println("Source Input Required.");
            return;
        }

        try {
            //Read all bytes from the filename.
            String s = new String(Files.readAllBytes(Paths.get(args[0])));
            //Use scanner to split the string.
            Scanner scan = new Scanner(s);
            //Count words
            while (scan.hasNext()){
                if(isWord(scan.next())) {
                    words++;
                }
            }
            //Close scanner obj
            scan.close();
            //Convert string to char array
            char[] chars = s.toCharArray();
            //Count chars
            for(char c : chars){
                //Check for new lines
                if(c == '\n') {
                    lines++;
                }else if(Character.isSpaceChar(c)){
                    //Above checks for spaces
                    spaces++;
                }else if(Character.isDigit(c)){
                    //Above checks for digits
                    numbers++;
                }else if(Character.isUpperCase(c)){
                    //Above checks for uppercase.
                    upperCase++;
                }else if(Character.isLowerCase(c)){
                    //Above checks for lowercase
                    lowerCase++;
                }else{
                    other++;
                }
            }
            letters = (upperCase + lowerCase);
            System.out.println("Letters    : " + letters);
            System.out.println("Uppercase  : " + upperCase);
            System.out.println("Lowercase  : " + lowerCase);
            System.out.println("Words      : " + words);
            System.out.println("Numbers    : " + numbers);
            System.out.println("Spaces     : " + spaces);
            System.out.println("Lines      : " + lines);
            System.out.println("Other      : " + other);

        }catch (IOException e){
            System.out.print(e.getMessage());
        }
    }
}