A collection of utility libraries for Kotlin and Java development.

This repository contains a modular collection of utility libraries designed to simplify and enhance Kotlin and Java development. Each module focuses on a specific domain or framework, providing extension functions, DSLs, and utility classes that reduce boilerplate code and improve developer productivity.

Three modules — core-utils, json-utils, and ktor-client-utils — are built with Kotlin Multiplatform and can be used from JVM, JS, wasmJs, and Native (iOS/macOS/tvOS/watchOS/Linux/Windows) projects. Their portable APIs live in commonMain; JVM-specific functions (e.g. hashing, URL codecs, classpath resources) remain available to JVM consumers unchanged via jvmMain. The remaining modules are JVM-only, as they integrate JVM-specific frameworks.

Fundamental utility functions and extensions for common programming tasks.

• String, number, and collection utilities
• I/O operations with security enhancements
• Atomic operations and thread-safe delegates
• Date/time formatting and duration helpers (DateUtils), zone-neutral by default
• Reflection utilities

Utilities for Dropwizard Metrics integration.

• Metrics DSL for cleaner configuration
• Health check utilities
• JMX integration helpers

Enhancements for JetBrains Exposed SQL framework.

• Custom SQL expressions
• UPSERT statement support
• Database operation utilities

gRPC server and client utilities.

• Server configuration DSL
• TLS/SSL utilities for secure communication
• Server extension functions

Google Guava integration and extensions.

• Concurrent programming utilities
• Service lifecycle management
• Thread-safe monitoring and waiting mechanisms
• Archive (ZIP) processing utilities

Jetty 12 (EE11) web server integration utilities.

• Server configuration DSL
• Lambda-based servlet implementations (Jakarta Servlet 6.1)
• Version endpoint utilities

Ktor HTTP client enhancements.

• Client configuration DSL
• Request/response utilities

Ktor server-side utilities.

• Heroku HTTPS redirect feature
• Response handling utilities
• Server configuration helpers

JSON processing utilities with Kotlinx.serialization.

• JsonElement extension functions for easy data access
• Nested path navigation with dot notation
• Multiple JSON format configurations (pretty, raw, lenient, strict)
• Type-safe value extraction with null safety

Prometheus metrics integration.

• Metrics DSL for clean metric definitions
• System metrics collection
• Instrumented thread factories
• Custom gauge collectors

Zipkin distributed tracing utilities.

• Tracing configuration DSL
• Span management utilities

Redis client utilities and extensions.

• Connection management
• Common Redis operation patterns
• Jedis client enhancements

Common base classes and interfaces for scripting engines.

• Abstract engine implementations
• Script pool management
• Expression evaluator frameworks

JavaScript engine integration.

• JavaScript execution utilities
• Script pooling for performance

Kotlin script engine integration.

• Kotlin script execution
• Expression evaluation
• Script compilation and caching

Python (Jython) script engine integration.

• Python script execution via Jython
• Expression evaluation capabilities

Email sending utilities using Resend.

• Email composition and sending via Resend API
• Resend webhook message handling
• HTML email support via Ktor HTML builder

Google reCAPTCHA verification utilities.

• reCAPTCHA configuration and service
• Server-side verification via Ktor HTTP client

Service lifecycle and configuration management.

• Generic service base classes
• Admin interface configuration
• Metrics service integration
• Servlet service management
• Zipkin reporting service

This library is available on Maven Central.

dependencies {
    // Include specific modules as needed
  implementation("com.pambrose.common-utils:core-utils:3.2.0")
  implementation("com.pambrose.common-utils:json-utils:3.2.0")
  implementation("com.pambrose.common-utils:ktor-server-utils:3.2.0")
    // ... other modules
}

For the multiplatform modules (core-utils, json-utils, ktor-client-utils), Maven consumers must depend on the -jvm artifact (e.g. core-utils-jvm); Gradle consumers resolve the correct variant from the root coordinate automatically. The JVM-only modules keep their plain artifact ids.

<dependencies>
    <dependency>
        <groupId>com.pambrose.common-utils</groupId>
        <artifactId>core-utils-jvm</artifactId>
      <version>3.2.0</version>
    </dependency>
    <!-- Add other modules as needed -->
</dependencies>

• Languages: Kotlin 2.4.10, Java
• Build System: Gradle 9.6.1 with Kotlin DSL
• Testing: Kotest, MockK
• Serialization: Kotlinx.serialization
• Concurrency: Kotlin Coroutines, Guava
• Web Frameworks: Ktor, Jetty 12 (EE11)
• Metrics: Dropwizard Metrics, Prometheus
• Databases: JetBrains Exposed
• Caching: Redis (Jedis)
• Tracing: Zipkin, Brave

# Show every available make target with descriptions
make help

# Build all modules
./gradlew build

# Build without tests
make build

# Run tests
./gradlew test

# Run tests for a specific module
./gradlew :core-utils:test

# Lint check (Kotlinter + Detekt)
make lint

# Detekt static analysis only
make detekt

# Aggregated Kover coverage reports (HTML + XML)
make coverage

This project maintains high code quality standards:

• Linting: Kotlinter (ktlint) and Detekt (config in config/detekt/)
• Testing: Comprehensive test coverage with Kotest
• Coverage: Kotlinx Kover with aggregated HTML/XML reports and Codecov upload from CI
• Security: Regular dependency updates and security reviews
• Documentation: Comprehensive module documentation

1. Create module directory with build.gradle.kts
2. Add module to settings.gradle.kts
3. Create module-specific README.md
4. Follow existing package structure: com.pambrose.common.*
5. Add comprehensive tests using Kotest

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Follow the existing code style and conventions
4. Add tests for new functionality
5. Update documentation as needed
6. Submit a pull request

Licensed under the Apache License, Version 2.0. See License.txt for details.

For questions, issues, or contributions, please use the GitHub issue tracker.