Citadel Interview Questions and Answers

Q1. What is the Singleton pattern ? in how many ways can this pattern be broken ?
Ans. 
Singleton pattern ensures a class has only one instance and provides a global point of access to it.
• Singleton pattern can be implemented by making the constructor private and providing a static method to access the instance.

• The pattern can be broken by using reflection to access the private constructor and create multiple instances.

• Another way to break the Singleton pattern is by using multiple class loaders in Java.

• Th...read more
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Q2. What is the internal implementation of hashmap? Let's assume that you want to store duplicate keys in the hashmap, how can we achieve the same in hashmap ?
Ans. 
HashMap internally uses an array of linked lists to store key-value pairs. To store duplicate keys, we can use a custom implementation of HashMap.
• HashMap internally uses an array of linked lists to handle collisions.

• To store duplicate keys, we can create a custom HashMap implementation that allows multiple values for the same key.

• One approach is to use a HashMap with values as lists, where each key can have multiple va
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Q1. What microservices patterns are you aware ? let's assume that there is a microservice based architecture and service A is calling service B which in turn service C. If service b fails, how will you manage ...read more
Ans. 
Use compensating transactions and distributed tracing for managing transaction and logging in case of service B failure.
• Implement compensating transactions to rollback changes made by service B in case of failure.

• Use distributed tracing to track the flow of requests and identify where the failure occurred.

• Implement retry mechanisms to handle transient failures in service B.

• Use circuit breakers to prevent cascading fail...read more
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Q2. System Design question : Design a booking wesite for.eg: bookin.com ?
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Q1. Life insurance is very important . why Life insurance is important?
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Q2. What expectations your life insurance?
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Q1. What's name? Please enter your name and your personal details?
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Q2. Please give me questions answers and I help you any problem?
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Q1. What expectations your salary?
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Q2. What's opinion your this company and this job?
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Q1. How important an honest person for the organisation's real growth?
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Q2. Should there be retirement if the person is fit?
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Q3. Should not there be the pension for an honest employee after atleast 5years of one's job with the organisation?
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3 coding que easy,med and hard

Q1. Os related que What is kernel , OS types ,what happens after booting computr ,etc
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Q2. Creat a array and print all elements , which database used for pdf storing sql or nosql
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Q1. OOps related que abstraction , inheritance , code it
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Q2. Middel element of linked list
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Q1. What challenges u faced in engineering?
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Q2. Situational based questions
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Q1. Why u choose to work deustch bank ?
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Q2. Project related quw
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