Bank Account Number (Generic Sensitive) Regex for Java

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching bank account number (generic sensitive), ported and verified for Java. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.

Java Implementation

// Bank Account Number (Generic Sensitive)
// ReDoS-checked | RegexVault — Identity & PII > Financial PII

import java.util.regex.Pattern;

public class BankAccountNumberGenericSensitiveValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^[0-9]{6,18}$");

    public static boolean validate(String input) {
        return PATTERN.matcher(input).matches();
    }

    // Example
    public static void main(String[] args) {
        System.out.println(validate("123456")); // true
    }
}

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Financial PII category and has been checked for ReDoS risk. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Bank account numbers vary widely by country: UK 8 digits, US 5-17 digits, Singapore 9-12 digits, India 11-16 digits. This pattern covers the practical range. Always combine with routing/sort code for unambiguous bank identification.