10. Strategy

Client code is agnostic of which concrete implementation is being used.

The strategies can be swapped at any time.

An interface defines a task. There may be many concrete implementations.

Once a strategy is defined it cannot be changed.

You always have fixed number of predefined strategies to choose from.

When the task is defined using an abstract class.

When the task is a functional interface.

You cannot use lambdas to implement the strategy pattern.

Polymorphism determines which concrete method implementation gets called when invoking the task interface.

Each strategy has a single responsibility.

Static polymorphism determines which overloaded method gets called, based on the method signature.

The strategy pattern relies on the Liskov Substitution Principle, not polymorphism.