Java compressing Strings

Question

I need to create a method that receives a String and also returns a String.

Ex input: AAABBBBCC

Ex output: 3A4B2C

Well, this is quite embarrassing a

Answer 1

package com.tell.datetime;

import java.util.Stack;
public class StringCompression {
    public static void main(String[] args) {
        String input = "abbcccffffdd";
        System.out.println(compressString(input));
    }

    public static String compressString(String input) {

        if (input == null || input.length() == 0)
            return input;
        String finalCompressedString = "";
        String lastElement="";
        char[] charArray = input.toCharArray();
        Stack stack = new Stack();
        int elementCount = 0;
        for (int i = 0; i < charArray.length; i++) {
            char currentElement = charArray[i];
            if (i == 0) {
                stack.push((currentElement+""));
                continue;
            } else {
                if ((currentElement+"").equalsIgnoreCase((String)stack.peek())) {
                    stack.push(currentElement + "");
                    if(i==charArray.length-1)
                    {
                        while (!stack.isEmpty()) {

                            lastElement = (String)stack.pop();
                            elementCount++;
                        }

                        finalCompressedString += lastElement + "" + elementCount;
                    }else
                    continue;
                }

                else {
                    while (!stack.isEmpty()) {

                        lastElement = (String)stack.pop();
                        elementCount++;
                    }

                    finalCompressedString += lastElement + "" + elementCount;
                    elementCount=0;
                    stack.push(currentElement+"");
                }

            }
        }

        if (finalCompressedString.length() >= input.length())
            return input;
        else
            return finalCompressedString;
    }

}