Interface-Based Anonymous Inner Class Inference

Lambda expressions can automatically infer anonymous inner classes when implemneting single-method interfaces:

if (TextUtils.hasContent(config.getPassword()) || config.allowAnonymousAccess()) {
    final UserAuthManager authManager = new UserAuthManager(config);
    
    sshServer.setPasswordAuthenticator((username, password, session) -> {
        AuthCredentials credentials = config.allowAnonymousAccess() 
            ? new AnonymousAuth() 
            : new UserPassAuth(username, password);
        
        log.debug("Authentication type '{}' for user: {}", 
                 credentials.getClass().getSimpleName(), username);
        
        try {
            authManager.validateCredentials(credentials);
        } catch (AuthException ex) {
            log.debug("Authentication failed", ex);
            return false;
        }
        return true;
    });
}

This approach implements the PasswordAuthenticator interface, allowing complex authentication logic including anonymous login handling and credential validation.

Explicit Anonymous Class Instantiation

For classes requiring constructor invocation, explicit anonymous class creation is necessary:

public class ConnectionFactory extends BaseConnectionFactory

sshServer.setConnectionFactory(new ConnectionFactory() {
    @Override
    protected BaseConnection establishConnection(IoSession session) throws Exception {
        SocketAddress clientAddress = session.getRemoteAddress();
        boolean authorized = IpValidator.isAuthorized(clientAddress, 
                                                    ftpService, logger);
        return authorized ? super.establishConnection(session) : null;
    }
});

This pattern instantiates the ConnectionFactory with constructor invocation and method override for implementing IP-based access control.

Java Documentation Annotations

When documenting generic types in Java comments, angle brackets may cause rendering issues in IDEs:

/**
 * This can be replaced with `AndroidFragment<org.example.prefs.FtpPrefsFragment>()`
 * Using backticks preserves formatting while avoiding rendering problems
 */

Using backticks around generic type declarations ensures proper rendering in documentation comments.