How to determine how many number of palindromes can be formed from a given string?

I have a problem where I need to find a palindrome with lowest lexicographical value from the Input string.

Sample input-      Sample output-

aabcc              acbca

Explanation- Out of all the palindromes cabac and acbca, acbca is lowest lexicographically.

P.S- I want to do it in java.