Caracter que mais se repete

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Scanner;

public class Repeat {

	/**
	 * @ Alkamavo Comedor de Java
	 */
	public static int conta(char a, char[] n) {
		int result = 0;

		for (int i = 0; i < n.length; i++) {
			if (n[i] == a)
				result++;
		}
		return result;
	}

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		ArrayList<Integer> lux = new ArrayList<Integer>();
		char[] xptzebra = null;
		int max = 0;
		String xpto = in.nextLine().toUpperCase();
		for (int i = 0; i < xpto.length(); i++) {
			xptzebra = xpto.toCharArray();
		}
		for (int j = 0; j < xptzebra.length; j++) {
			max = conta(xptzebra[j], xptzebra);
			lux.add(max);
			Collections.sort(lux);
			System.out.println(xptzebra[j] + " " + max);

		}
		System.out.println("Mais digitado :" + " " + lux.get(lux.size() - 1));
	}

}