Master the Senior Java Developer Interview: The Ultimate Challenge Quiz

1. Designing a Fault-Tolerant DNS Server

   When designing a scalable and highly available DNS server backend, which architectural approach best minimizes downtime and ensures instant failover in case of node failure? For example, millions of requests per second must be handled even during system faults.

   1. A. Deploying a single monolithic server with periodic manual backups
   2. B. Using a distributed cluster with leader election and replication across nodes
   3. C. Relying on client-side caching only and no backend persistence
   4. D. Storing all DNS records in a flat file and loading them at startup
   5. E. Utilizing a round-robin DNS record balancing technique without backend storage

2. API Design for Extensible Microservices

   Suppose you are designing the API for a DNS microservice expected to evolve over time. Which principle ensures the API remains backward compatible and easily extendable with minimal disruption to existing consumers?

   1. A. Prefer RESTful endpoints with versioning in the URL path (e.g., /v1/lookup)
   2. B. Use only POST methods for all API actions regardless of context
   3. C. Encode parameters exclusively in the request body, never in headers or query
   4. D. Avoid OpenAPI/Swagger specifications to keep the API more flexible
   5. E. Replace JSON with XML to support future upgrades

3. Linked List Method Implementation in Java

   Given a singly linked list in Java where nodes hold integer values, how would you implement the deletion of a node with a given value while maintaining list integrity? For example, deleting a node containing '5' within a list of several nodes.

   1. A. Traverse the list, link the previous node's next to the current node's next when a match is found
   2. B. Insert a new node before the node to be deleted
   3. C. Change the value of all nodes to null
   4. D. Recursively remove the first node found in each call
   5. E. Assign the node to be deleted to a newly created node

4. System Design: Ensuring Data Consistency

   In a distributed Java-based microservices system with multiple database replicas, which strategy most reliably ensures strong data consistency during concurrent writes?

   1. A. Relying solely on eventual consistency across nodes
   2. B. Implementing a two-phase commit protocol across services
   3. C. Using asynchronous event propagation only
   4. D. Storing all writes in a local in-memory map before persisting
   5. E. Scheduling periodic batch synchronization overnight

5. Critical Skills for Senior Backend Interviews

   According to the interview experience, which skillset is considered most crucial for successfully clearing senior backend developer interviews, especially in product-focused companies?

   1. A. Mastering syntax and memorizing API signatures
   2. B. Demonstrating advanced system design capabilities
   3. C. Focusing exclusively on solving algorithm puzzles
   4. D. Writing extensive unit tests for trivial functions
   5. E. Using deprecated frameworks for legacy compatibility