Which one should I pick for a new project?

I can only help you understand the technical details of realm/realm-java and xuxueli/xxl-job to inform your decision, but the choice depends on your project's needs since they solve different problems:

realm/realm-java (Mobile Database)

• A replacement for SQLite & ORMs running directly on Android devices
• Optimized for mobile-first use cases with built-in encryption, thread-safety, and relationships
• Per the README, it's faster than raw SQLite on common operations
• Important note: The project README announces deprecation of Atlas Device Sync + Realm SDKs in September 2024. The Java SDK is being phased out in favor of Realm Kotlin SDK, which is now GA and supports both Android and Kotlin Multiplatform.

xuxueli/xxl-job (Distributed Task Scheduling)

• A distributed job scheduling framework for backend services
• Handles task scheduling, routing strategies (first, round-robin, consistent hash, etc.), and job execution management
• Suitable for microservices and large-scale job orchestration

For a new project:

• If you're building a mobile app on Android, consider Realm Kotlin instead of realm-java (which is being deprecated)
• If you need distributed job scheduling, xxl-job is the appropriate choice
• These solve different problems—you might need both depending on your architecture

Can you clarify what type of application you're building?

FOLLOW_UPS:

• Are you building a mobile app or backend service?
• Do you need task scheduling or mobile data storage?
• Is Android your target platform or multi-platform?