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Maintainability Foundation JAVA Practice Exam
Question 1. Which ISO/IEC 25010 characteristic directly describes the ease with which a software product can be modified? A) Reliability B) Maintainability C) Portability D) Security Answer: B Explanation: Maintainability is defined by ISO/IEC 25010 as the degree of effectiveness and efficiency with which a product can be modified. Question 2. In the business context, high maintainability primarily reduces which of the following? A) System performance B) Development costs for future changes C) User interface complexity D) Network latency Answer: B Explanation: High maintainability lowers the effort and cost required to make future modifications, thus reducing overall development expenses. Question 3. Which quality attribute is most closely related to maintainability when considering the impact of fixing defects?
Maintainability Foundation JAVA Practice Exam
A) Reliability B) Efficiency C) Usability D) Compatibility Answer: A Explanation: Reliability concerns fault tolerance; maintainability affects how easily those faults can be corrected, linking the two attributes. Question 4. Which type of maintenance involves adding new features to meet evolving business needs? A) Corrective B) Adaptive C) Perfective D) Preventive Answer: C Explanation: Perfective maintenance focuses on improving or extending functionality, such as adding new features. Question 5. Cyclomatic Complexity measures which aspect of a unit? A) Number of lines of code B) Number of decision points
Maintainability Foundation JAVA Practice Exam
Explanation: The Code Duplication Ratio quantifies the proportion of identical or near‑identical code fragments. Question 8. A “Large Class” smell violates which SOLID principle? A) Single Responsibility Principle (SRP) B) Open/Closed Principle (OCP) C) Liskov Substitution Principle (LSP) D) Interface Segregation Principle (ISP) Answer: A Explanation: SRP states a class should have one reason to change; a large class typically has many responsibilities. Question 9. Feature Envy occurs when a method: A) Calls many methods of another class more than its own B) Contains many nested loops C) Declares many local variables D) Is never invoked Answer: A Explanation: Feature Envy indicates a method is more interested in another class’s data than its own, suggesting misplaced functionality.
Maintainability Foundation JAVA Practice Exam
Question 10. Which refactoring extracts a group of related fields and methods into a new class? A) Extract Method B) Extract Class C) Move Method D) Inline Class Answer: B Explanation: Extract Class creates a new class to hold a cohesive subset of members, improving modularity. Question 11. The “Replace Conditional with Polymorphism” refactoring primarily addresses which code smell? A) Long Method B) Switch Statements C) Data Clumps D) Magic Numbers Answer: B Explanation: It removes extensive if‑else or switch logic by delegating behavior to subclasses. Question 12. Which Java language feature helps avoid “raw type” code smells?
Maintainability Foundation JAVA Practice Exam
C. LSP
D. ISP
Answer: B Explanation: The Open/Closed Principle (OCP) promotes extending behavior via inheritance or composition without altering existing code. Question 15. An immutable class in Java must have all of the following EXCEPT: A. All fields declared final B. No setter methods C. A public mutable collection field D. All fields initialized in the constructor Answer: C Explanation: A public mutable collection would allow external modification, breaking immutability. Question 16. Which of the following is a sign of “Shotgun Surgery” in a codebase? A. One class contains many unrelated methods B. A single change requires edits in many classes C. A method is excessively long D. Multiple classes have identical code blocks
Maintainability Foundation JAVA Practice Exam
Answer: B Explanation: Shotgun Surgery forces a developer to modify many places for a single logical change. Question 17. The “Introduce Explaining Variable” refactoring improves: A. Performance B. Readability C. Security D. Concurrency Answer: B Explanation: Naming intermediate results clarifies complex expressions for future readers. Question 18. Which collection type provides O(1) average‑time complexity for key‑based lookups? A. ArrayList B. LinkedList C. HashMap D. TreeSet Answer: C Explanation: HashMap uses hashing to achieve constant‑time key retrieval on average.
Maintainability Foundation JAVA Practice Exam
Question 21. Which metric assesses the balance of responsibilities among components? A. Component Coupling B. Component Balance C. Fan-in D. Depth of Inheritance Tree Answer: B Explanation: Component Balance measures how evenly responsibilities are distributed across components. Question 22. The “Extract Interface” refactoring is most useful for: A. Reducing code duplication B. Improving testability by decoupling clients from implementations C. Increasing cyclomatic complexity D. Eliminating magic numbers Answer: B Explanation: Introducing an interface allows clients to depend on abstractions, facilitating mocking and substitution. Question 23. Which of the following best describes “Message Chains”? A. A series of method calls that traverse multiple objects to get a needed value
Maintainability Foundation JAVA Practice Exam
B. Repeated identical code blocks C. Classes that expose many public fields D. Methods that have too many parameters Answer: A Explanation: Message Chains indicate a violation of Law of Demeter, making code fragile. Question 24. A “Lazy Class” is identified when: A. The class has no public methods B. The class does not contain enough functionality to justify its existence C. The class inherits from many super‑classes D. The class contains only static methods Answer: B Explanation: Lazy Class indicates an unnecessary abstraction that can be merged elsewhere. Question 25. Which design pattern replaces a complex conditional with a family of interchangeable objects? A. Singleton B. Strategy C. Factory Method
Maintainability Foundation JAVA Practice Exam
Explanation: Vague abbreviations reduce readability; constants should be self‑explanatory. Question 28. The “Depth of Inheritance Tree” metric measures: A. Number of interfaces implemented B. Maximum length from a class to the root of the inheritance hierarchy C. Number of overridden methods D. Amount of code duplication across subclasses Answer: B Explanation: DIT reflects inheritance depth, influencing complexity and understandability. Question 29. Which principle encourages small, client‑specific interfaces rather than one large interface? A. SRP B. OCP C. ISP D. DIP Answer: C Explanation: Interface Segregation Principle (ISP) advises splitting interfaces so clients only depend on what they use.
Maintainability Foundation JAVA Practice Exam
Question 30. In Java, which construct is preferred for handling resources that must be closed, such as streams? A. finally block B. try‑with‑resources C. System.gc() D. Thread.sleep() Answer: B Explanation: try‑with‑resources automatically invokes close() on resources, ensuring proper cleanup. Question 31. Which of the following best describes “Dead Code”? A. Code that is never executed at runtime B. Code that throws unchecked exceptions C. Code that uses deprecated APIs D. Code that has high cyclomatic complexity Answer: A Explanation: Dead code is unreachable or never called, adding maintenance overhead without functional benefit. Question 32. Which refactoring technique would you apply to a method that takes ten parameters? A. Extract Method
Maintainability Foundation JAVA Practice Exam
D. They are typically automated. Answer: B Explanation: Unit tests verify individual components but do not cover interactions between components; integration testing is still needed. Question 35. Which of the following is a benefit of using the final keyword on method parameters? A. Improves runtime performance by enabling inlining B. Prevents the parameter from being reassigned within the method, enhancing readability C. Allows the method to be overridden in subclasses D. Enforces thread‑safety automatically Answer: B Explanation: Declaring a parameter final ensures it cannot be reassigned, making the method’s intent clearer. Question 36. In a CI pipeline, which automated check directly supports maintainability? A. Load testing B. Static code analysis for code smells C. Database migration scripts D. User acceptance testing
Maintainability Foundation JAVA Practice Exam
Answer: B Explanation: Static analysis tools detect violations of maintainability guidelines early in the development process. Question 37. Which of the following is an example of a “Magic Number”? A. final int MAX_RETRIES = 5; B. if (status == 200) { … } without a named constant C. enum Day { MONDAY, TUESDAY } D. String.format("%s", name) Answer: B Explanation: Hard‑coded literals like 200 without a descriptive name are magic numbers, reducing readability. Question 38. The “Law of Demeter” encourages which of the following? A. Deep inheritance hierarchies B. Limited knowledge of other objects’ internal structures C. Use of global variables for sharing state D. Frequent use of static methods Answer: B Explanation: It advises that a class should only talk to its immediate collaborators, preventing message chains.
Maintainability Foundation JAVA Practice Exam
A. One class is modified in many unrelated ways over time B. Multiple classes need to be changed for a single feature C. A class contains many static methods D. A method has a very high cyclomatic complexity Answer: A Explanation: Divergent Change indicates a class has multiple responsibilities, leading to frequent unrelated edits. Question 42. In Java, which annotation indicates that a method is intended to be a unit test? A. @Test B. @Override C. @Deprecated D. @FunctionalInterface Answer: A Explanation: @Test (from JUnit) marks a method as a test case. Question 43. Which metric is most directly affected by the number of if/else statements in a method? A. Lines of Code (LOC) B. Cyclomatic Complexity
Maintainability Foundation JAVA Practice Exam
C. Depth of Inheritance Tree (DIT) D. Weighted Methods per Class (WMC) Answer: B Explanation: Each decision point (if/else, case, while) increments cyclomatic complexity. Question 44. Which design principle is violated when a subclass overrides a method and changes its expected behavior for existing clients? A. Open/Closed Principle B. Liskov Substitution Principle C. Interface Segregation Principle D. Dependency Inversion Principle Answer: B Explanation: LSP requires that objects of a subclass can be substituted for objects of the superclass without altering desirable properties. Question 45. Which of the following is NOT a characteristic of a well‑structured Java package hierarchy? A. Logical grouping by feature or layer B. Mixing unrelated utilities with core domain classes in the same package C. Avoiding cyclic dependencies between packages D. Using meaningful package names that reflect purpose
