Find duplicate characters in a String and count the number of occurances using Java

Question

How can I find the number of occurrences of a character in a string?

For example: The quick brown fox jumped over the lazy dog.

Some example

Answer 1

import java.util.Scanner;

    class Test
    { 

        static String s2="";
        int l;
        void countDuplicateCharacters(String Str)
        {
            String S=Str.toLowerCase();
            for(int i=0;i