ddd4j Kit

Overview

Prefer the stable utilities already shipped by ddd4j. Avoid duplicating them in business modules. Always confirm a tool's null handling, exception contract, type semantics, and thread safety before adopting it.

When to Use

• Finding an existing utility before writing a private one: StrKit, CollKit, ArrayKit, IdKit, DateKit, ReflectKit.
• Choosing the right JsonKit mapper per scenario: DEFAULT_OBJECT_MAPPER for ordinary JSON, REDIS_OBJECT_MAPPER for trusted cache data, EventPayloadSerializer for events.
• Deciding between BeanKit and MappingKit for bean property handling, and where implicit copying is unsafe.
• Verifying a utility's null handling, exception contract, and generics before adopting it.
• Working with the Jackson 2 / 3 boundary, including the com.fasterxml.jackson.annotation compatibility package.
• Removing duplicate utility wrappers that Kit already provides.

When NOT to Use

Do not use this skill when: