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.HashMap;
import java.util.Scanner;


public class HashMapDemo {

    public static void main(String[] args) {
        //Create HashMap object to Store Element as Key and Value 
        HashMap hm= new HashMap();
        //Enter Your String From Console
        System.out.println("Enter an String:");
        //Create Scanner Class Object From Retrive the element from console to our java application
        Scanner sc = new Scanner(System.in);
        //Store Data in an string format
        String s1=sc.nextLine();
        //find the length of an string and check that hashmap object contain the character or not by using 
        //containskey() if that map object contain element only one than count that value as one or if it contain more than one than increment value 

        for(int i=0;i