30 real Behavioral 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 Observer?
Junior
A.a pattern that passes a request along a chain of handlers until one of them handles it, decoupling sender from receiver
B.a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
C.a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
D.a pattern that defines a one-to-many dependency so when one object changes state all its dependents are notified automatically, the basis of pub-sub
2. Which term means: "a pattern that defines a one-to-many dependency so when one object changes state all its dependents are notified automatically, the basis of pub-sub"?
A.Observer — a pattern that represents an operation to perform on the elements of an object structure, letting you add new operations without changing the element classes
B.Observer — a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
C.Observer — a pattern that defines a one-to-many dependency so when one object changes state all its dependents are notified automatically, the basis of pub-sub
D.Observer — a pattern that passes a request along a chain of handlers until one of them handles it, decoupling sender from receiver
A.a pattern that passes a request along a chain of handlers until one of them handles it, decoupling sender from receiver
B.a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
C.a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly
D.a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
5. Which term means: "a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it"?
A.Strategy — a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
B.Strategy — a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
C.Strategy — a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly
D.Strategy — a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
A.a pattern that lets an object alter its behavior when its internal condition changes, appearing to change its class
B.a pattern that represents an operation to perform on the elements of an object structure, letting you add new operations without changing the element classes
C.a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
D.a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
A.Command — a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
B.Command — a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
C.Command — a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
D.Command — a pattern that provides sequential access to the elements of an aggregate object without exposing its underlying representation
A.a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
B.a pattern that lets an object alter its behavior when its internal condition changes, appearing to change its class
C.a pattern that represents an operation to perform on the elements of an object structure, letting you add new operations without changing the element classes
D.a pattern that passes a request along a chain of handlers until one of them handles it, decoupling sender from receiver
14. Which term means: "a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure"?
A.Template Method — a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly
B.Template Method — a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
C.Template Method — a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
D.Template Method — a pattern that provides sequential access to the elements of an aggregate object without exposing its underlying representation
17. Which term means: "a pattern that provides sequential access to the elements of an aggregate object without exposing its underlying representation"?
A.Iterator — a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
B.Iterator — a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
C.Iterator — a pattern that provides sequential access to the elements of an aggregate object without exposing its underlying representation
D.Iterator — a pattern that lets an object alter its behavior when its internal condition changes, appearing to change its class
A.a pattern that passes a request along a chain of handlers until one of them handles it, decoupling sender from receiver
B.a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
C.a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
D.a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
A.Chain of Responsibility — a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly
B.Chain of Responsibility — a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
C.Chain of Responsibility — a pattern that passes a request along a chain of handlers until one of them handles it, decoupling sender from receiver
D.Chain of Responsibility — a pattern that defines a one-to-many dependency so when one object changes state all its dependents are notified automatically, the basis of pub-sub
A.a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
B.a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
C.a pattern that defines a one-to-many dependency so when one object changes state all its dependents are notified automatically, the basis of pub-sub
D.a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly
23. Which term means: "a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly"?
A.a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
B.a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
C.a pattern that provides sequential access to the elements of an aggregate object without exposing its underlying representation
D.a pattern that represents an operation to perform on the elements of an object structure, letting you add new operations without changing the element classes
26. Which term means: "a pattern that represents an operation to perform on the elements of an object structure, letting you add new operations without changing the element classes"?
A.Visitor — a pattern that defines the skeleton of an algorithm in a base method, deferring some steps to subclasses without changing the overall structure
B.Visitor — a pattern that lets an object alter its behavior when its internal condition changes, appearing to change its class
C.Visitor — a pattern that represents an operation to perform on the elements of an object structure, letting you add new operations without changing the element classes
D.Visitor — a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
A.a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation
B.a pattern that encapsulates a request as an object, letting you parameterize, queue, log, and undo operations
C.a pattern that defines a family of interchangeable algorithms, encapsulates each one, and lets the algorithm vary independently from clients that use it
D.a pattern that centralizes complex communication between objects in one mediating object so they no longer refer to each other directly
29. Which term means: "a pattern that captures and externalizes an object's internal state so it can be restored later without violating encapsulation"?
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