SQL Questions: • Difference between WHERE and HAVING • JOIN clauses and their use cases and a question on that • optimize a SQL query Core Java / Backend: • What is the Executor Framework? • Polymorphism (with examples) • final vs abstract • Circuit Breaker pattern Some spring framework question LLD (Low-Level Design): • Builder pattern – what it is and when to use it • Factory pattern – what it is and where it fails • Which SOLID principle is violated in Factory pattern (and why) DSA: • Valid Parentheses problem
