*Java Coding Challenge: Part 20 – Find the First Repeating Character in a String* *Challenge:* Write a Java program to find the first repeating character in a string. *Example:* Input: "programming" Output: 'r' (‘r’ is the first character that repeats) *Approach:* 1. Traverse the string one character at a time. 2. Use a HashSet to track seen characters. 3. The first character that’s already in the set is the answer. *Java Code:* import java.util.HashSet; public class FirstRepeatingChar { public static void main(String[] args) { String input = "programming"; char result = findFirstRepeatingChar(input); if (result != '\0') { System.out.println("First repeating character: " + result); } else { System.out.println("No repeating character found."); } } public static char findFirstRepeatingChar(String str) { HashSet seen = new HashSet<>(); for (char ch : str.toCharArray()) { if (seen.contains(ch)) { return ch; } seen.add(ch); } return '\0'; // null character if no repeating character is found } } If you want to find the first non-repeating character, use a LinkedHashMap to preserve the order and count frequency. *React ❤️ for Part 21*