Objects contained in a Pool must implement the Poolable interface and adhere to its contract. Pools call allocate on Allocators with the specific Slot that they want a Poolable allocated for. The Slot represents a location in the pool, that can fit an object and make it available for others to claim. The contract of the Poolable interface is, that when release() is called on the Poolable, it must in turn call Slot#release(Poolable) on the specific Slot object that it was allocated with, giving itself as the Poolable parameter. A simple correct implementation of the Poolable interface looks like this: [source,java] ---- include::../src/test/java/examples/Examples.java[tag=poolableGenericExample] ---- This can be shortened further by extending the BasePoolable class: [source,java] ---- include::../src/test/java/examples/Examples.java[tag=poolableBaseExample] ---- It is also possible to directly use the Pooled implementation, which implements both `Poolable` and AutoCloseable, and holds a reference to the actual object being pooled. Memory effects: The release of an object happens-before it is claimed by another thread, or deallocated.