SuccessivePlay

import java.util.ArrayList;
import java.util.Collections;

public class Action {
    public static void main(String[] args) {

        long start = System.nanoTime();
        String givenNumber = "75478569123456871234567854123456701234567892452655";
        String foundNumber = findTheLargestSuccessiveNumber(givenNumber);
        long elapsedTime = System.nanoTime() - start;
        System.out.print("time: " + elapsedTime + " nanoseconds"
                        + "\nLargest successive Number: " + foundNumber );
    }
    public static String findTheLargestSuccessiveNumber(String givenNumber) {
        String finalFoundNumber = "0";
        int tempFoundNumber = 0;
        int length = givenNumber.length();
        ArrayList<String> list = new ArrayList<>();
        ArrayList<Integer> list2 = new ArrayList<>();
        int x = 0;
        for (int i = 0; i<length; i++) {
            x = Character.getNumericValue(givenNumber.charAt(i));
            if(x == tempFoundNumber + 1) {
                finalFoundNumber = finalFoundNumber + x;
                tempFoundNumber = Integer.valueOf(finalFoundNumber);
                list.add(finalFoundNumber);
            }else {
                finalFoundNumber = "";
            }
            tempFoundNumber = x;
        }
        int aLength = list.size();
        for(int i = 0; i < aLength; i++) {
            list2.add(Integer.parseInt(list.get(i).toString()));
        }
        finalFoundNumber = String.valueOf(Collections.max(list2));
        return finalFoundNumber;
    }

}