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Low-Level Design
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Low-Level Design
Behavioral Patterns: Observer, Command, Strategy, Template Method & Chain of Responsibility
Low-Level Design
Concurrency Patterns: Thread Safety, Producer-Consumer, Read-Write Lock & Thread Pool
Low-Level Design
Structural Patterns: Proxy, Adapter, Facade, Composite & Decorator
Structural design patterns define how classes and objects are composed into larger structures. Master Proxy (lazy loading, access control, caching), Adapter (interface translation), Facade (simplified subsystem interface), Composite (tree structures), and Decorator (dynamic behavior extension) — each with Java examples and real interview applications.
Structural Patterns: Composing Objects into Larger Systems
Structural patterns are about how objects and classes are assembled into larger structures while keeping those structures flexible and efficient. They solve the recurring problem of adapting interfaces, adding behavior without modifying classes, and organizing hierarchies without tightly coupling components.
Unlike creational patterns (which instantiate objects) and behavioral patterns (which define communication), structural patterns focus on relationships: wrapping, delegating, composing. The key insight across all structural patterns is delegation over inheritance — rather than extending a class to add behavior, you wrap it or compose it.