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Question 1. Which Java concept allows an object to take many forms, enabling code reuse and flexibility? A) Encapsulation B) Inheritance C) Polymorphism D) Abstraction Answer: C Explanation: Polymorphism in Java allows objects to be treated as instances of their parent class or interface, enabling a single interface to represent different underlying data types, thus enhancing flexibility and reusability. Question 2. In Java, which collection implementation provides constant-time performance for add, remove, and contains operations? A) ArrayList
B) HashSet C) LinkedList D) TreeMap Answer: B Explanation: HashSet offers constant-time performance (O(1)) for add, remove, and contains operations under ideal conditions due to its underlying hash table structure. Question 3. Which Java keyword is used to restrict access to a class member to within its own class? A) private B) protected C) public D) static
Question 5. What is the primary purpose of the synchronized keyword in Java? A) To improve performance B) To prevent thread interference C) To enable thread creation D) To handle exceptions Answer: B Explanation: The synchronized keyword ensures that only one thread at a time can execute a block of code or method, preventing race conditions and thread interference. Question 6. Which Java Stream API method is used to perform an operation on each element of a stream?
A) map() B) filter() C) forEach() D) reduce() Answer: C Explanation: The forEach() method performs an action for each element in the stream, often used for side effects like printing or updating external variables. Question 7. Which cloud service model provides a platform allowing users to develop, run, and manage applications without managing underlying infrastructure? A) IaaS B) PaaS
Explanation: AWS Lambda allows running code in response to events without provisioning or managing servers, enabling serverless architectures. Question 9. Which networking component in cloud environments isolates network traffic for different virtual networks? A) Subnet B) VPC/VNet C) Security Group D) Load Balancer Answer: B Explanation: VPC (Virtual Private Cloud) or VNet (Virtual Network) isolates network traffic within a cloud environment, providing a private network space.
Question 10. Which IAM principle ensures that users and services have only the permissions necessary to perform their tasks? A) Role-based access control B) Principle of Least Privilege C) Mandatory Access Control D) Discretionary Access Control Answer: B Explanation: The Principle of Least Privilege restricts access rights for users and services to only what is necessary, reducing security risks. Question 11. Which cloud storage service is best suited for storing unstructured data such as images, videos, and backups? A) Relational Database B) Object Storage
Explanation: STANDARD_IA (Infrequent Access) offers low-cost storage for data accessed less frequently but requires rapid access when needed. Question 13. Which Java data type is best suited for storing large text data? A) int B) String C) StringBuilder D) char[] Answer: B Explanation: The String class is used for storing text data. For mutable large text data, StringBuilder is preferable, but String is suitable for most text storage needs.
Question 14. Which Java exception is thrown when an attempt is made to divide an integer by zero? A) NullPointerException B) ArithmeticException C) IOException D) ClassCastException Answer: B Explanation: Dividing an integer by zero in Java throws an ArithmeticException, indicating illegal arithmetic operation. Question 15. Which Java class is used for reading text data from a character input stream efficiently? A) InputStreamReader B) BufferedReader
Explanation: Generics enable compile-time type checking, reducing runtime errors and increasing code safety by specifying the type of objects in collections. Question 17. Which Java feature was introduced in Java 8 to support functional programming? A) Lambda expressions B) Annotations C) Generics D) Inner classes Answer: A Explanation: Lambda expressions were introduced in Java 8 to enable functional programming by allowing inline implementation of functional interfaces.
Question 18. In Java, which interface must a class implement to be executed by an ExecutorService? A) Runnable B) Callable C) Future D) Executor Answer: A Explanation: To be executed by an ExecutorService, a task must implement Runnable or be submitted as a Callable; Runnable is the most common. Question 19. Which Java feature allows multiple threads to execute code concurrently within a single process? A) Multithreading
Answer: B Explanation: ObjectOutputStream serializes Java objects to an OutputStream, enabling object persistence and network transmission. Question 21. In Java, which control flow statement is used to execute a block of code repeatedly based on a condition? A) if B) switch C) for D) break Answer: C Explanation: The for loop executes a block of code repeatedly as long as its condition remains true, supporting iteration.
Question 22. Which data structure in Java provides constant-time add, remove, and contains operations due to its hash table implementation? A) HashMap B) TreeMap C) HashSet D) LinkedList Answer: C Explanation: HashSet uses a hash table, providing constant-time performance for add, remove, and contains operations under ideal conditions. Question 23. Which Java feature allows a method to operate on objects of different classes through a common interface? A) Encapsulation B) Inheritance
Explanation: IOException and FileNotFoundException are checked exceptions that must be handled during file I/O operations in Java. Question 25. Which Java construct is used to handle exceptions that occur during runtime? A) try-catch-finally B) if-else C) switch-case D) synchronized Answer: A Explanation: The try-catch-finally construct is used to handle exceptions, allowing graceful recovery from runtime errors.
Question 26. Which cloud provider's compute service uses "Compute Engine"? A) AWS B) GCP C) Azure D) IBM Cloud Answer: B Explanation: Google Cloud Platform's (GCP) primary compute service is called Compute Engine, providing scalable virtual machines. Question 27. Which AWS service is best suited for deploying containerized applications managed with Kubernetes? A) EC B) EKS
