Java vs Python for Tech Interviews 2026

Design a distributed rate limiter that can handle 10M requests per second across multiple data centers. Discuss consistency tradeoffs, the choice between token bucket vs leaky bucket, and how you would handle clock skew across regions.

What is the difference between String, StringBuilder, and StringBuffer in Java? When would you use each? Explain immutability, thread safety, performance implications, and give an example where using String in a loop causes excessive object creation.

Given a binary tree, return the boundary of the tree in anti-clockwise direction starting from the root. The boundary consists of the left boundary, leaves, and the right boundary in reverse.

What are the SOLID principles? Explain each with a real-world Java example. Then describe a scenario where rigidly following SOLID leads to over-engineering, and how you balance pragmatism with good design.

Design a data pipeline to ingest CDC (Change Data Capture) events from a MySQL database into a Snowflake data warehouse in near real-time.

Design an AI content moderation system for a social platform with 10 million daily posts. How do you balance accuracy, cost, and latency?

You need to run a DAG that processes 10,000 files daily — one task per file. How do you design this in Airflow without creating 10,000 static tasks?

How would you reduce the latency of a RAG pipeline from 4 seconds to under 1 second in production?