Do effectively immutable objects make sense?

Question

In the book Java Concurrency In Practice it explains the advantages of \"effectively immutable\" objects versus mutable objects concurrency-wise. But it does not explain what a

Answer 1

Using effectively immutable objects lets you avoid creating a considerable number of classes. Instead of making pairs of [mutable builder]/[immutable object] classes, you can build one effectively immutable class. I usually define an immutable interface, and a mutable class that implements this interface. An object is configured through its mutable class methods, and then published through its immutable interface. As long as the clients of your library program to the interface, to them your objects remain immutable through their published lifetime.