FrequencyOOPS.java

import java.util.*;
import java.util.Scanner;
import java.util.ArrayList;

public class FrequencyOOPS {
    public static void main(String[] args){
        Scanner sc= new Scanner(System.in);
        
        System.out.println("Enter the first text :- ");
        String text1= sc.nextLine();
        System.out.println("For " + text1);
        frequency(text1);

        System.out.println("Enter the second text :- ");
        String text2= sc.nextLine();
        System.out.println("For " + text2);
        frequency(text2);

    }

    private static void frequency(String s){
        if (s.length() == 0){
            System.out.println("String is empty");
        }

        ArrayList<CharOccur> occurences= new ArrayList<CharOccur>();

        for(int i=0;i<s.length();i++){

            char c= s.charAt(i);
            int flag=0;

            for(CharOccur o : occurences){
                if(o.character == c ){
                    o.occurence += 1;
                    flag=1;
                }

            }

            if(flag == 0){
                CharOccur grp= new CharOccur(c,1);
                occurences.add(grp);
            }
        }
        for(CharOccur o : occurences){
            System.out.println(o.character + " " + o.occurence);
            }
    }

}


class CharOccur{
    char character;
    int occurence=0;

    CharOccur(char character, int occurence){
        this.character= character;
        this.occurence= occurence;
    }
}