How to generate a random alphanumeric string in Java?

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Good approach, @ishrth_fathima But if you’re working in a multi-threaded environment, there’s a better way to ensure efficiency and avoid potential performance bottlenecks."*

Instead of using Random, which can be problematic in high-concurrency scenarios, ThreadLocalRandom is a more optimized choice:

import java.util.concurrent.ThreadLocalRandom;

public class RandomStringGenerator {
    public static void main(String[] args) {
        String characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        StringBuilder result = new StringBuilder();
        
        for (int i = 0; i < 17; i++) {
            int index = ThreadLocalRandom.current().nextInt(characters.length());
            result.append(characters.charAt(index));
        }
        
        System.out.println("Random String: " + result.toString());
    }
}

Why use ThreadLocalRandom? Because it’s specifically designed for concurrent applications, eliminating contention issues that might occur with Random. So if you’re working in a multi-threaded scenario, this is a better java generate random string approach.