Strategy Pattern

Strategy is one of the most practical behavioral patterns in Java because it addresses a common design pressure: one task can be carried out in several legitimate ways, and the choice should be explicit.

Modern Java gives Strategy two strong implementation styles:

• classic interfaces and concrete strategy classes
• functional strategies using lambdas or method references

The pattern is strongest when it removes conditional sprawl and keeps algorithm choice visible. It is weakest when a plain function parameter would have been enough and a whole object hierarchy is invented out of habit.

In this section

• Implementing Strategy in Java
  Implement Strategy in Java by separating the stable context from the interchangeable algorithm contract and making the choice explicit.
• Functional Strategies with Lambdas
  Use lambdas for Java strategies when the behavior is small and the strategy contract is naturally functional.
• Context and Strategy Interfaces in the Strategy Pattern
  Design Java Strategy contexts and contracts so the variable behavior is isolated without leaking too much context into the strategy.
• Strategy Pattern Use Cases and Examples in Java
  See where Strategy genuinely helps in Java systems, from pricing and ranking to retry policies, serialization choices, and routing rules.