Answer: When designing a scalable and fault-tolerant Java application, there are several key factors to consider: Distributed Architecture: Use a distributed architecture that allows the application to scale horizontally across multiple nodes. A microservices architecture is a popular choice for building distributed applications. Load Balancing: Implement load balancing to distribute incoming requests evenly across the nodes. This ensures that no single node becomes overloaded with requests. Caching: Use caching to reduce the load on the application's backend servers. Caching frequently accessed data in memory can significantly improve the application's performance. Resilience: Design the application with resilience in mind. Use techniques like circuit breakers and retries to handle failures in the backend services. Monitoring: Implement comprehensive monitoring to quickly detect and respond to failures. This includes monitoring the application's performance, resource utilization, and error rates. Testing: Test the application thoroughly to ensure that it can handle the expected load and failure scenarios. As a Java Technical Lead, it's important to have a deep understanding of the underlying technology stack and to be able to design robust and scalable solutions.