Infosys Software Engineer - Java Developer interview questions

Technical Round: Q1. Explain the Spring Security. Q2. Explain the flow of a Rest API call from frontend to backend and response back to frontend. Q3. Explain JWT token. Q4. Define Filters and Segmentation in Spring Security. Q5. How one microservices authenticate another microservice with jwt? Q6. What is a functional interface? Q7. Give an example of a java interface which uses a functional interface. Q8. Write a code to implement Runnable using lambda. Q9. Which is springboot default server and How to use another server in srpingboot? Q10. What are profiles and how to use them? Q11. How is bean Injection working? Q12. How to inject a specific bean of the same object? Q13. How to set up a discovery server? Like Eureka Q14. What is the use of @Primary annotation? Q15. Which method can we use to check if a service is up or not? Q16. How would you externalize a microservice? Q17. What is the default port of springboot? Q18. What is an optional class and its use? Q19. Optional.Of() vs Optional.ofNullable() Q20. Write sql query to return 2nd highest salary. Q21. What is a Rest template?

in HR round they will asks for PF,Form 16 unfortunately my current company is a small startup and we don't have these so i got rejected by them