}

    @Override
    public String getUserDomain() {
        if (this.realm == null && this.getSubject() != null) {
            Set<Principal> pr = this.getSubject().getPrincipals();
            for (Iterator<Principal> ite = pr.iterator(); ite.hasNext();) {
                try {
                    KerberosPrincipal entry = (KerberosPrincipal) ite.next();
                    return entry.getRealm();

mvn license:format
```

### Code Style

- Follow Java coding conventions
- Use proper JavaDoc comments for public APIs
- Include unit tests for new functionality
- Ensure all tests pass before submitting PR

## License