21 real Structural questions from the Design Patterns bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Adapter?
Junior
A.a pattern that converts the interface of one class into another interface clients expect, letting incompatible types work together
B.a pattern that provides a surrogate or placeholder for another object to control access to it
C.a pattern that composes objects into tree structures so clients treat individual objects and groups uniformly
D.a pattern that provides a unified simplified interface to a set of interfaces in a complex subsystem
2. Which term means: "a pattern that converts the interface of one class into another interface clients expect, letting incompatible types work together"?
A.Adapter — a pattern that decouples an abstraction from its implementation so the two can vary independently
B.Adapter — a pattern that minimizes memory use by sharing as much intrinsic state as possible across many fine-grained objects
C.Adapter — a pattern that converts the interface of one class into another interface clients expect, letting incompatible types work together
D.Adapter — a pattern that attaches additional responsibilities to an object dynamically by wrapping it, offering a flexible alternative to subclassing
5. Which term means: "a pattern that attaches additional responsibilities to an object dynamically by wrapping it, offering a flexible alternative to subclassing"?
A.Decorator — a pattern that provides a unified simplified interface to a set of interfaces in a complex subsystem
B.Decorator — a pattern that converts the interface of one class into another interface clients expect, letting incompatible types work together
C.Decorator — a pattern that attaches additional responsibilities to an object dynamically by wrapping it, offering a flexible alternative to subclassing
D.Decorator — a pattern that minimizes memory use by sharing as much intrinsic state as possible across many fine-grained objects
A.Composite — a pattern that composes objects into tree structures so clients treat individual objects and groups uniformly
B.Composite — a pattern that attaches additional responsibilities to an object dynamically by wrapping it, offering a flexible alternative to subclassing
C.Composite — a pattern that decouples an abstraction from its implementation so the two can vary independently
D.Composite — a pattern that provides a unified simplified interface to a set of interfaces in a complex subsystem
A.Flyweight — a pattern that attaches additional responsibilities to an object dynamically by wrapping it, offering a flexible alternative to subclassing
B.Flyweight — a pattern that provides a surrogate or placeholder for another object to control access to it
C.Flyweight — a pattern that decouples an abstraction from its implementation so the two can vary independently
D.Flyweight — a pattern that minimizes memory use by sharing as much intrinsic state as possible across many fine-grained objects
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