10+ GfK MODE Interview Questions and Answers

C++ is an extension of C with object-oriented programming features.

• C++ supports classes and objects while C does not.

• C++ has better support for polymorphism and inheritance.

• C++ has a standard template library (STL) while C does not.

• C++ allows function overloading while C does not.

• C++ has exception handling while C does not.

No, Kafka relies on ZooKeeper for cluster coordination and management.

• ZooKeeper is used for leader election, configuration management, and synchronization in Kafka clusters.

• Kafka brokers register themselves in ZooKeeper and use it to discover other brokers and partitions.

• Without ZooKeeper, Kafka cannot function as a distributed system.

• However, Kafka can be run in standalone mode without ZooKeeper for development and testing purposes.

Replications ensure fault tolerance and high availability of data in Kafka.

• Replications provide redundancy and ensure that data is not lost in case of node failures.

• They also improve read performance by allowing consumers to read from multiple replicas.

• Replications can be configured to have different levels of consistency guarantees.

• For example, a replication factor of 3 ensures that data is stored on 3 different nodes.

• If one node fails, the data can still be retrieved from t...read more

Pointers are variables that store memory addresses. Inheritance is a way to create new classes based on existing ones.

• Pointers allow direct access to memory locations, enabling efficient manipulation of data.

• In C++, pointers can be used to dynamically allocate memory.

• Inheritance allows for code reuse and the creation of more specialized classes.

• For example, a Car class can inherit from a Vehicle class, inheriting its properties and methods.

Use self join and delete to remove duplicate records in SQL

• Use a self join to identify duplicate records based on specific criteria

• Select the records to be deleted using the self join

• Use the DELETE statement to remove the duplicate records

Microservice is a software architecture pattern where an application is built as a collection of small, independent services.

• Microservices are independently deployable and scalable.

• Each microservice performs a specific business function.

• Communication between microservices is usually done through APIs.

• Microservices can be written in different programming languages and use different data storage technologies.

• Examples of companies using microservices include Netflix, Amazon, and...read more

Scope defines the visibility of variables, transient is short-lived, and singleton is a single instance shared across the application.

• Scope determines the visibility and lifetime of variables in a program.

• Transient objects are short-lived and are typically used for temporary data storage.

• Singleton pattern ensures a class has only one instance and provides a global point of access to it.

A Consumer Group is a group of consumers that collectively consume messages from one or more topics.

• Consumer Groups allow for parallel processing of messages from a topic

• Each consumer group maintains its own offset for each partition of a topic

• Multiple consumer groups can consume messages from the same topic

• Consumer Groups are commonly used in Apache Kafka

Web services are software systems designed to support interoperable machine-to-machine interaction over a network.

• Web services allow different applications to communicate with each other over the internet.

• They use standardized protocols like HTTP, XML, SOAP, and REST.

• Web services can be used for a variety of purposes, such as sharing data between different systems or integrating different applications.

• Examples of web services include Google Maps API, Amazon Web Services, and ...read more

staticmethod and class method are two types of methods in Python classes.

• staticmethod is a method that belongs to a class but does not have access to the class or instance.

• classmethod is a method that belongs to a class and has access to the class but not the instance.

• staticmethod is used when a method does not need to access the class or instance.

• classmethod is used when a method needs to access the class but not the instance.

• Example of staticmethod: @staticmethod def method...read more

I have used 'django.db.models' package in my Django models.

• The 'django.db.models' package provides the base classes for defining models in Django.

• It includes classes like 'Model', 'CharField', 'IntegerField', 'ForeignKey', etc.

• These classes are used to define the fields and relationships in a Django model.

• For example, 'class MyModel(models.Model): name = models.CharField(max_length=50)'

• This creates a model with a 'name' field that is a character field with a maximum length of...read more

Dependency injection is a design pattern in which components are given their dependencies rather than creating them internally.

• Allows for easier testing by mocking dependencies

• Promotes loose coupling between components

• Improves code reusability and maintainability

• Examples: Constructor injection, Setter injection, Interface injection

ZooKeeper is a distributed coordination service for managing configuration, synchronization, and naming.

• ZooKeeper provides a hierarchical namespace for distributed systems.

• It is used for maintaining configuration information, naming, providing distributed synchronization, and group services.

• ZooKeeper is used in Apache Hadoop, Apache Kafka, and Apache Storm.

• It uses a consensus protocol called ZAB (ZooKeeper Atomic Broadcast) to maintain consistency and order among servers.

Sorting is the process of arranging items in a specific order, typically in ascending or descending order.

• Sorting helps in organizing data for easier retrieval and analysis.

• Common sorting algorithms include bubble sort, merge sort, and quick sort.

• Example: Sorting a list of numbers in ascending order: [5, 2, 8, 1] -> [1, 2, 5, 8]

Indexes are data structures used to improve the speed of data retrieval operations in databases.

• Indexes are created on columns in database tables to quickly locate rows based on the values in those columns.

• They help in reducing the number of disk I/O operations required when querying data.

• Examples include primary keys, unique keys, and indexes created on frequently searched columns.

Sorting in a dictionary

• Use sorted() function to sort the dictionary by keys or values

• Use lambda function to sort the dictionary by custom key

• Use OrderedDict() to maintain the order of the sorted dictionary

MVC life cycle involves request handling, routing, controller execution, view rendering, and response generation.

• Request is received by the router

• Router maps the request to the appropriate controller

• Controller processes the request and interacts with the model

• Model updates the data and sends it back to the controller

• Controller passes data to the view for rendering

• View generates the response and sends it back to the client