XXL-JOB is a distributed task scheduling framework designed for rapid development, simplicity, and lightweight operation. It consists of a scheduler center (admin) and multiple executors. The admin provides a web UI for CRUD job management, scheduling (cron, fix rate, fix delay), routing strategies (first, last, round, random, consistent hash, LFU, LRU, failover, busyover, sharding broadcast), misfire handling, alarm (email), and monitoring. Executors run on any JVM and communicate with the admin via Netty-based HTTP RPC. The framework supports BEAN (annotated methods), GLUE (online Groovy/script editing), script tasks (Shell, Python, PHP, NodeJS, PowerShell), HTTP tasks, and AI tasks (Ollama, Dify, OpenClaw). It includes an OpenAPI for cross-language integration, user management with role-based permissions, and Docker deployment. The architecture is modular: xxl-job-core provides the executor runtime and shared interfaces, xxl-job-admin is the Spring Boot admin application, and sample executors demonstrate integration. External dependencies include MySQL (persistence), Netty (executor server), Groovy (glue tasks), and Spring Boot. The framework is production-ready with HA support for both scheduler and executor clusters.
HMCL (Hello Minecraft! Launcher) is a cross-platform Minecraft launcher written in Java using JavaFX. It manages game instances (install, update, launch), downloads game files and mod loaders (Forge, Fabric, NeoForge, Quilt, LiteLoader, etc.), supports multiple authentication methods (offline, Microsoft, Yggdrasil, authlib-injector), and handles modpacks (CurseForge, Modrinth, MultiMC, etc.). The architecture is a monolith with three modules: HMCL (UI), HMCLCore (core logic), and HMCLBoot (bootstrap). It features a custom task framework for async operations, an event bus, a wizard system for multi-step dialogs, and extensive hardware detection (CPU, GPU, memory) across Windows, macOS, and Linux. The codebase is well-structured but contains copied external libraries (JFoenix skins, APNG reader) and some tight coupling between UI and core modules.