Newbie Solution

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        
        Scanner sc=new Scanner(System.in);
        String A=sc.next();
        String B=sc.next();
        /* Enter your code here. Print output to STDOUT. */
        int sum = A.length() + B.length();
        System.out.println(sum);
        int lengthToConsider = A.length()>B.length()?B.length():A.length();
        for(int i=0;i<lengthToConsider;++i){
            if(i == A.length()-1 || i== B.length()-1){
                System.out.println("No");
                break;
            }
            if(A.charAt(i)==B.charAt(i))continue;
            if((int)A.charAt(i)>(int)B.charAt(i)){
                System.out.println("Yes");
                break;
            }else{
                System.out.println("No");
                break;
            }       
        }
        A=A.substring(0,1).toUpperCase()+A.substring(1,A.length());
        B=B.substring(0,1).toUpperCase()+B.substring(1,B.length());        
        System.out.printf("%s %s",A,B);
        
    }
}

import java.util.*;

public class Solution {

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    String B=sc.next();

    System.out.println(A.length()+B.length());        
    if(A.compareTo(B)>0){
        System.out.println("Yes");
    }
    else
    {
        System.out.println("No");
    }
    System.out.println(A.substring(0,1).toUpperCase()+A.substring(1)+" "+B.substring(0,1).toUpperCase()+B.substring(1));

     sc.close();;           
}

}

Strings in Java are immutable, so every invocation of .substring(), .replace() , .toUpperCase() or concatenation with + creates a new String object. Thus, I prefer converting a String to character array or use StringBuilder class that encapsulates a mutable buffer and provides a set of methods to operate on it in a meaningful name. In the end, it creates a new String, of course, but it scales well with the number of applied operations.

My solution looks as follows:

import java.util.Scanner;

public class Solution {
    private static String capitalizeFirst(String str) {
        StringBuilder sb = new StringBuilder(str);
        sb.setCharAt(0, Character.toUpperCase(str.charAt(0)));
        return sb.toString();
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.nextLine();
        String b = sc.nextLine();
        sc.close();
        System.out.println(a.length() + b.length());
        System.out.println((a.compareTo(b) > 0) ? "Yes" : "No");
        System.out.println(capitalizeFirst(a) + " " + capitalizeFirst(b));
    }
}

import java.io.; import java.util.;

public class Solution {

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    String B=sc.next();
    /* Enter your code here. Print output to STDOUT. */
    int len = A.length()+B.length();
    String s = "No";
    if(A.compareTo(B)>0){
        s = "Yes";
    }
    String capA = A.substring(0,1).toUpperCase();
    String capB = B.substring(0,1).toUpperCase();
    System.out.printf("%d\n%s\n%s %s", len,s,capA+A.substring(1),capB+B.substring(1));
    sc.close();
}

}

mport java.io.; import java.util.;

public class Solution {

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    String B=sc.next();
    /* Enter your code here. Print output to STDOUT. */
            //1
    System.out.println(A.length()+B.length());
    //2
    if (A.compareTo(B) > 0) {
        System.out.println("Yes");
    } else {
        System.out.println("No");
    }

    //3
    System.out.println(A.replace(A.charAt(0), A.toUpperCase().charAt(0))  +" "+B.replace(B.charAt(0), B.toUpperCase().charAt(0)));

}

}