Airtel Africa Senior Big Data Developer Interview Questions and Answers

Q1. How to optimise fetching 1 lakh entries from db
Ans. 
Use pagination, indexing, caching, and query optimization to fetch 1 lakh entries efficiently from the database.
• Implement pagination to fetch data in smaller chunks

• Create indexes on columns frequently used in queries

• Use caching to store frequently accessed data

• Optimize queries by avoiding unnecessary joins and using appropriate indexes

• Consider using database-specific optimizations like query hints or stored procedures
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Q1. Difference between streams and parallel streams
Ans. 
Streams process elements sequentially, while parallel streams process elements concurrently.
• Streams process elements one by one in a sequential manner.

• Parallel streams process elements concurrently, potentially utilizing multiple threads for faster processing.

• Streams are suitable for smaller datasets or when order matters.

• Parallel streams are more efficient for larger datasets or when order is not important.

• Example: St...read more
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Q2. What is Static keyword in Java do?
Ans. 
Static keyword in Java is used to create class-level variables and methods that can be accessed without creating an instance of the class.
• Static variables are shared among all instances of a class.

• Static methods can be called without creating an object of the class.

• Static keyword can be used to initialize a variable only once.

• Example: public static int count = 0;
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Q1. What is method overloading and overriding
Ans. 
Method overloading is when multiple methods have the same name but different parameters. Method overriding is when a subclass provides a specific implementation of a method that is already provided by its superclass.
• Method overloading allows a class to have multiple methods with the same name but different parameters.

• Method overriding occurs in a subclass when a method has the same name, return type, and parameters as ...read more
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Q2. Program to swap two variables without using third
Ans. 
Swapping two variables without using a third variable
• Use XOR operation to swap two variables without using a third variable

• Example: a = 5, b = 10; a = a ^ b; b = a ^ b; a = a ^ b; // Now a = 10, b = 5
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Q1. Why you want to join this organization
Ans. 
I am impressed by the organization's innovative projects and collaborative work culture.
• Impressed by innovative projects

• Attracted to collaborative work culture

• Excited about potential for growth and learning opportunities
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Q2. What is your weakness and strength
Ans. 
My weakness is overthinking and my strength is attention to detail.
• Weakness: tend to overthink situations, which can lead to indecision or unnecessary stress

• Strength: strong attention to detail, ensuring accuracy and quality in my work

• Example: I sometimes spend too much time analyzing a problem before taking action, but I have learned to set deadlines for myself to prevent this from affecting my productivity
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Q1. What are the things that u do when your what app screen is blank
Ans. 
I would check for internet connection, restart the app, clear cache, and update the app.
• Check internet connection

• Restart the app

• Clear cache

• Update the app
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Q2. Simple python code
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Q1. Memory management in java 8
Ans. 
Java 8 introduced improvements in memory management with features like Metaspace and G1 garbage collector.
• Java 8 introduced Metaspace to replace the PermGen space for class metadata storage.

• G1 garbage collector in Java 8 improves garbage collection performance by dividing the heap into regions.

• Java 8 also introduced the concept of String deduplication to reduce memory usage for String objects.
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Q2. CQRS pattern in microservices
Ans. 
CQRS pattern separates read and write operations in microservices for better scalability and performance.
• CQRS stands for Command Query Responsibility Segregation

• It separates the read and write operations in microservices

• Write operations update the data, while read operations retrieve the data

• Helps in improving scalability and performance by optimizing for each operation type
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Test had 2 sections..first section had 3 subsections with quants,verbal and logicals.2nd section is an English writing skill round where they give u a topic and u have to write ur views on it more than 200 words

Gd has the basic rules..they give a topic and u have to discuss on that

Q1. Hr asks you questions on your project,the programming language ur strong in and may be few code solving questions
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Q1. HR round tests your flexibility and adaptability skills.
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