Use the Specification pattern in Java to encode business rules as reusable predicates that can be composed, tested, and translated across boundaries.
The Specification pattern packages business rules into reusable objects or predicates that can be combined with logical operations such as and, or, and not. In Java, it is especially useful when rule logic must stay readable across validation, querying, filtering, and domain-model code.
The pattern earns its keep when rules need reuse, composition, or translation into another boundary such as a repository query. It is weaker when the rule is simple enough that a plain predicate or well-named method already says everything clearly.
This section focuses on that trade-off. The child pages cover implementation, rule composition, and practical use cases so you can judge when Specification clarifies Java business logic and when it only adds a new abstraction layer around ordinary predicates.