HTTP Strict-Transport-Security Header Regex for Java
/^max-age=([0-9]+)(?:;\s*includeSubDomains)?(?:;\s*preload)?$/iWhat this pattern does
This page provides a well-structured, multi-part regular expression for matching http strict-transport-security header, ported and verified for Java. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.
Java Implementation
// HTTP Strict-Transport-Security Header
// ReDoS-safe | RegexVault — Security > Security Headers
import java.util.regex.Pattern;
public class HttpStricttransportsecurityHeaderValidator {
private static final Pattern PATTERN =
Pattern.compile("^max-age=([0-9]+)(?:;\\s*includeSubDomains)?(?:;\\s*preload)?$");
public static boolean validate(String input) {
return PATTERN.matcher(input).matches();
}
// Example
public static void main(String[] args) {
System.out.println(validate("max-age=31536000")); // true
}
}Test Cases
Matches (Valid) | Rejects (Invalid) |
|---|---|
max-age=31536000 | max-age=-1 |
max-age=31536000; includeSubDomains | max-age=abc |
max-age=31536000; includeSubDomains; preload | includeSubDomains; max-age=31536000 |
max-age=0 | max-age=31536000; preload; includeSubDomains |
When to use this pattern
This pattern is drawn from the Security > Security Headers 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
Setting preload without also setting includeSubDomains is invalid for preload list inclusion. Setting max-age=0 with preload in place creates a catch-22 — contact hstspreload.org for removal (takes months).
Technical Notes
HSTS tells browsers to only connect via HTTPS. min max-age for HSTS preloading: 31536000 (1 year). max-age=0 disables HSTS. includeSubDomains extends to all subdomains. preload submits to Chrome/Firefox preload lists — be careful, it is very hard to undo. Capture group 1: max-age value in seconds.
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