api-design

To design a Java library API that hides implementation details, expose minimal public surfaces using interfaces and records instead of concrete classes. This approach maintains proper encapsulation and ensures long-term API stability for external consumers.

Use interfaces to define behavior contracts, records for simple data carriers, and enums for fixed constant sets in public Java APIs. Selecting the appropriate construct maximizes implementation hiding and establishes clear, stable module boundaries for external consumers.

The best way to migrate concrete Java classes to an SPI without breaking compatibility is to introduce interfaces and factory methods. This refactoring approach enables safe API evolution by decoupling external consumers from internal implementations while maintaining modular boundaries.

Yes, you can use Java records to define module boundaries for external consumers. Records provide a clean, immutable way to transfer data across API boundaries while interfaces handle behavioral contracts, together ensuring a minimal and stable public API surface.

Safely evolve a Java library API with minimal breaking changes by using factory methods, Service Provider Interfaces (SPIs), and modularization. These constructs allow you to update internal implementations and add features without altering the published public interface contracts.

Exposing concrete classes in a Java API hinders long-term evolution because external consumers can directly access and depend on internal fields and implementations. This tight coupling forces breaking changes whenever internal logic must be updated or refactored.