Hermes ⚡¶

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High-performance logging library for Java with excellent developer experience

Inspired by SLF4J, Hermes is a modern logging library that focuses on performance and developer productivity. Named after the Greek messenger god, Hermes delivers your log messages swiftly and reliably.

Features¶

🚀 Zero-boilerplate logging - Use @InjectLogger annotation for automatic logger field injection
⚡ High performance - Async logging with LMAX Disruptor and zero-allocation optimization
🎯 Fluent API - Parameterized logging with {} placeholders
⚙️ Easy configuration - Configure via application.yaml with sensible defaults
🔧 Spring Boot integration - Auto-configuration support
🧵 Thread-safe - Built for concurrent applications
📝 MDC support - Mapped Diagnostic Context for contextual logging
🎨 Markers - Tag and categorize log messages
📁 Multiple appenders - Console, File, RollingFile, Async with Disruptor
📊 JSON structured logging - Built-in JSON layout for log aggregation
🎯 Pattern layouts - Customizable log output patterns

Quick Example¶

import io.github.dotbrains.InjectLogger;

@InjectLogger
public class UserService extends UserServiceHermesLogger {

    public void createUser(String username) {
        log.info("Creating user: {}", username);

        try {
            saveToDatabase(username);
            log.info("User {} created successfully", username);
        } catch (Exception e) {
            log.error("Failed to create user: {}", username, e);
        }
    }
}

Why Hermes?¶

Zero Boilerplate¶

No more typing private static final Logger log = LoggerFactory.getLogger(ClassName.class); in every class. Just add @InjectLogger and extend the generated base class.

Performance First¶

Zero-allocation logging with ThreadLocal StringBuilder
Async logging powered by LMAX Disruptor for 10M+ logs/second
Early exit optimization to avoid formatting when level is disabled

Modern Java¶

Built for Java 17+, leveraging records, text blocks, and other modern features. Fully compatible with GraalVM native-image.

Getting Started¶

Head over to the Quick Start Guide to begin using Hermes in your project.

Architecture¶

Hermes follows a modular architecture:

hermes-api: Core interfaces and annotations
hermes-core: High-performance implementation
hermes-processor: Annotation processor for @InjectLogger
hermes-spring-boot-starter: Spring Boot auto-configuration
hermes-kotlin: Kotlin DSL extensions
hermes-examples: Example applications

Learn more in the Architecture Overview.

Comparison with SLF4J¶

Feature	SLF4J	Hermes
Logger injection	Manual or Lombok	`@InjectLogger` annotation
Configuration	XML/Properties	YAML with sensible defaults
Async logging	Via Logback/Log4j	Built-in with Disruptor
Performance	Good	Optimized for zero-allocation
Spring Boot	External starters	Native integration
Java version	8+	17+ (modern Java features)

License¶

MIT License - see LICENSE file for details