Add Java Solution for Chewbacca's Digit Inversion Problem

[Prathamesh-1011]

Description:
This issue is for adding a Java solution to solve the problem where Chewbacca wants to minimize a number by inverting some of its digits. Inverting a digit involves replacing it with 9 - t (where t is the original digit), ensuring that the resulting number is the smallest possible positive number and does not contain leading zeros.

Problem Description:
Input: A single integer x (1 ≤ x ≤ 10^18).
Output: The smallest possible number after inverting some digits, without leading zeros.

Constraints:
The input number x can be as large as 10^18, so it needs to be handled as a string or long integer to avoid overflow.
The number should not start with zero after inverting any digits.

Sample Input
4545
Sample Output
4444
Explanation
There are many numbers form after inverting the digit. For minimum number, check if inverting digit is less than or greater than the original digit. If it is less, then invert it otherwise leave it.

[Prathamesh-1011]

@Kavya-24 Please assign me this under the Octoberfest 2024 Label :) and a good first issue