Wipro Interview Questions

Wipro Limited is a multinational corporation headquartered in Bengaluru, India, specializing in information technology, consulting, and business process services. Founded in 1945 by Mohamed Premji, the company initially focused on vegetable oil production before transitioning to IT services in the 1980s.

Wipro provides a wide range of services, including software development, system integration, and digital transformation. It operates globally with a significant presence in North America, Europe, and Asia.

Certainly! Here are 20 common technical interview questions for Wipro, along with detailed answers to help you prepare:

1.What are the main principles of Object-Oriented Programming (OOP)?

Answer: OOP is based on four main principles:

• Encapsulation: Bundling data and methods that operate on the data within a single unit or class. It hides the internal state of an object from the outside world.
• Inheritance: A mechanism where a new class inherits properties and behaviors (methods) from an existing class. This promotes code reusability.
• Polymorphism: The ability to present the same interface for different underlying data types. It allows methods to do different things based on the object it is acting upon.
• Abstraction: Hiding the complex implementation details and showing only the necessary features of an object. It simplifies interactions by focusing on high-level functionalities.

2. Explain the concept of normalization in databases.

Answer: Normalization is a process used to design relational databases to minimize redundancy and dependency. It involves organizing tables and columns to reduce data duplication. The primary normal forms are:

• First Normal Form (1NF): Ensures that the table has only atomic (indivisible) values and each column contains unique values.
• Second Normal Form (2NF): Requires the table to be in 1NF and that all non-key attributes are fully functionally dependent on the entire primary key.
• Third Normal Form (3NF): Requires the table to be in 2NF and that all the attributes are only dependent on the primary key, eliminating transitive dependencies.

3. How does a hash table work?

Answer: A hash table is a data structure that uses a hash function to map keys to values. The hash function computes an index (hash code) in an array where the value is stored. This allows for average-case constant-time complexity (O(1)) for operations like insertion, deletion, and lookup. However, collisions (when two keys hash to the same index) are handled through techniques such as chaining (storing multiple elements in a list at the same index) or open addressing (finding another slot within the array).

4. What is the difference between SQL and NoSQL databases?

Answer:

• SQL Databases: These are relational databases that use Structured Query Language (SQL) for defining and manipulating data. They follow a fixed schema and support ACID (Atomicity, Consistency, Isolation, Durability) properties. Examples include MySQL, PostgreSQL, and Oracle.
• NoSQL Databases: These are non-relational databases designed for unstructured data and scalability. They support various data models like key-value pairs, document-oriented, column-family, or graph. They are more flexible in schema design and are suitable for handling large volumes of diverse data types. Examples include MongoDB, Cassandra, and Redis.

5. Describe the different types of join operations in SQL.

Answer: Joins are used to retrieve data from multiple tables based on a related column. Common types include:

• INNER JOIN: Returns rows where there is a match in both tables.
• LEFT JOIN (or LEFT OUTER JOIN): Returns all rows from the left table and the matched rows from the right table. Unmatched rows from the right table will contain NULL.
• RIGHT JOIN (or RIGHT OUTER JOIN): Returns all rows from the right table and the matched rows from the left table. Unmatched rows from the left table will contain NULL.
• FULL JOIN (or FULL OUTER JOIN): Returns all rows when there is a match in one of the tables. Rows without a match in either table will contain NULL.

6. What is the difference between a stack and a queue?

Answer:

• Stack: Follows a Last In First Out (LIFO) principle. The last element added is the first to be removed. Common operations include push (add an element) and pop (remove the top element). It is used in scenarios like function call management and undo operations.
• Queue: Follows a First In First Out (FIFO) principle. The first element added is the first to be removed. Common operations include enqueue (add an element) and dequeue (remove the front element). It is used in scenarios like task scheduling and buffering.

7. Explain the concept of recursion.

Answer: Recursion is a programming technique where a function calls itself directly or indirectly to solve a problem. A recursive function must have:

• Base Case: A condition under which the recursion stops to prevent infinite loops.
• Recursive Case: The part of the function that includes the recursive call. It breaks the problem into smaller instances of the same problem. For example, calculating factorials or traversing hierarchical structures can be efficiently handled using recursion.

8. What are the differences between GET and POST methods in HTTP?

Answer:

• GET: Used to request data from a specified resource. Data is appended to the URL as query parameters. It is idempotent (repeated requests have the same effect) and is suitable for read-only operations. It has length limitations and can be cached.
• POST: Used to submit data to be processed to a specified resource. Data is included in the request body, not in the URL. It is not idempotent (repeated requests can have different effects) and is used for operations that alter the server state (e.g., form submissions).

9. What is a deadlock in operating systems, and how can it be prevented?

Answer: A deadlock is a situation in operating systems where a set of processes are blocked because each process is holding a resource and waiting for another resource held by another process, creating a cycle of dependencies. To prevent deadlocks:

• Avoid Circular Wait: Ensure that resources are requested in a consistent order.
• Prevent Resource Holding: Require processes to request all resources at once.
• Preempt Resources: Allow resource preemption by taking resources away from one process to satisfy another.
• Detect and Recover: Implement algorithms to detect deadlocks and take actions to recover, such as terminating or restarting processes.

10. What is a memory leak, and how can it be prevented?

Answer: A memory leak occurs when a program allocates memory but fails to release it after use, leading to increased memory consumption and eventually causing performance degradation or crashes. To prevent memory leaks:

• Proper Resource Management: Ensure all allocated memory is released appropriately.
• Use Smart Pointers: In languages like C++, use smart pointers that automatically manage memory.
• Conduct Regular Code Reviews: Check for potential leaks during code reviews and testing.
• Employ Memory Leak Detection Tools: Use tools like Valgrind or built-in diagnostic tools to identify leaks.

11. What is the difference between static and dynamic polymorphism?

Answer:

• Static Polymorphism: Achieved through method overloading or operator overloading. The method to be invoked is determined at compile time. For example, having multiple methods with the same name but different parameters in the same class.
• Dynamic Polymorphism: Achieved through method overriding, where a subclass provides a specific implementation of a method that is already defined in its superclass. The method to be invoked is determined at runtime based on the object type.

12. What is the purpose of the final keyword in Java?

Answer: The final keyword in Java has several uses:

• Final Variable: The value cannot be changed once initialized.
• Final Method: The method cannot be overridden by subclasses.
• Final Class: The class cannot be subclassed.

13. Explain the concept of a design pattern.

Answer: Design patterns are reusable solutions to common problems in software design. They provide best practices for solving design issues and are categorized into three types:

• Creational Patterns: Deal with object creation mechanisms (e.g., Singleton, Factory Method).
• Structural Patterns: Deal with object composition and class structure (e.g., Adapter, Composite).
• Behavioral Patterns: Deal with object interactions and responsibilities (e.g., Observer, Strategy).

14. What is the difference between process and thread?

Answer:

• Process: A process is an independent program that runs in its own memory space. Processes are isolated from each other and communicate through inter-process communication (IPC).
• Thread: A thread is a lightweight unit of execution within a process. Threads share the same memory space and resources of the parent process, allowing for more efficient communication and coordination within a process.

15. What is a RESTful API?

Answer: A RESTful API (Representational State Transfer) is a web service that adheres to REST principles, which include:

• Stateless Communication: Each request from a client to a server must contain all the information needed to understand and process the request.
• Client-Server Architecture: The client and server are separate entities, allowing for scalability.
• Uniform Interface: A consistent and standardized interface for communication (e.g., using HTTP methods like GET, POST, PUT, DELETE).
• Resource-Based: Resources are identified by URLs, and interactions are performed using standard HTTP methods.

16. What is the difference between a linked list and an array?

Answer:

• Array: A data structure that stores elements in contiguous memory locations. It provides fast access (O(1)) by index but has a fixed size and requires resizing operations for dynamic changes.
• Linked List: A data structure where elements (nodes) are stored in non-contiguous memory locations. Each node points to the next node in the sequence. It allows for dynamic resizing and efficient insertions/deletions but has slower access time (O(n)) compared to arrays.

17. Explain the concept of exception handling in programming.

Answer: Exception handling is a mechanism used to manage runtime errors in a program. It allows a program to continue executing even if an error occurs. Common concepts include:

• Try Block: Contains code that might throw an exception.
• Catch Block: Contains code to handle the exception if it occurs.
• Finally Block: Contains code that executes regardless of whether an exception was thrown or not (e.g., for resource cleanup).
• Throw Statement: Used to explicitly throw an exception.
• Throws Clause: Declares that a method may throw exceptions, allowing the caller to handle them.

18. What is the difference between an abstract class and an interface in Java?

Answer:

• Abstract Class: Can have both abstract methods (without implementation) and concrete methods (with implementation). It can also have member variables and constructors. A class can inherit from only one abstract class due to single inheritance.
• Interface: Can only have abstract methods (until Java 8, after which default and static methods are also allowed). Interfaces are used to define a contract for classes to implement. A class can implement multiple interfaces, supporting multiple inheritance.

19. What is the significance of the volatile keyword in Java?

Answer: The volatile keyword in Java indicates that a variable's value will be modified by different threads. It ensures visibility of the variable's changes to all threads and prevents caching of the variable's value. This guarantees that the latest value is always read from the main memory and not from a thread's local cache.

20. What are lambda expressions in Java?

Answer: Lambda expressions, introduced in Java 8, provide a concise way to represent anonymous functions. They enable the implementation of functional interfaces (interfaces with a single abstract method) using a more readable and compact syntax. For example, a lambda expression for a functional interface MyFunction with a method apply might look like: MyFunction func = (x) -> x * 2;.

These detailed answers should help you prepare for a technical interview at Wipro or similar companies. Good luck with your preparation!