TLD Validation (2–6 Character) Regex for Java
/^[a-zA-Z]{2,6}$/What this pattern does
This page provides a lightweight, single-purpose regular expression for matching tld validation (2–6 character), ported and verified for Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.
Java Implementation
// TLD Validation (2–6 Character)
// ReDoS-safe | RegexVault — Web & Network > Domain
import java.util.regex.Pattern;
public class TldValidation26CharacterValidator {
private static final Pattern PATTERN =
Pattern.compile("^[a-zA-Z]{2,6}$");
public static boolean validate(String input) {
return PATTERN.matcher(input).matches();
}
// Example
public static void main(String[] args) {
System.out.println(validate("com")); // true
}
}Test Cases
Matches (Valid) | Rejects (Invalid) |
|---|---|
com | c |
net | toolongtld |
org | c0m |
io | .com |
co | COM. |
museum | — |
When to use this pattern
This pattern is drawn from the Web & Network > Domain category and carries a ReDoS-safe certification. 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
TLD validation by regex alone is not authoritative — use the IANA TLD list or a library like publicsuffix-list for production use.
Technical Notes
New gTLDs (e.g., .photography, .construction) can be up to 24 characters. Adjust the upper bound to {2,24} if validating modern TLDs. The IANA TLD list is the authoritative source.
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