Round 1: SOLID Principles, Abstraction, Inheritance, Immutable Class Internal working of concurrent hashmap & hashset Contract between equals and hashcode Can we insert Employee e1 = new Employee(1, "Name") & Employee e12= new Employee(1, "Name") in a Hashmap ? If yes, what will be the size How will the decision be made during insertion. What design patterns have you used? Explain Singleton design pattern. Give an example for factory design pattern. How do you write unit tests? Difference between @Mock & @Inject Explain try with resources. If a class is passed as resource in try then what should be taken care at the class level ? How to make custom exceptions ? Questions on exception handling About kafka messaging - how microservices interact ? Explain consumer publisher event mechanism What do you do when one of the microservice is down ? How to do fault tolerance ? Do your microservices share DB ? If yes, how is concurrency maintained in that case How to add custom configurations to spring boot application? Which will be considered if a spring boot application has both application.yml & application.properties files ? If there are multiple beans with same name, how to prioritise one bean over others ? How to create custom annotations? SQL Question: Consider a list of employees, filter out the employees whose salary is > 50000 and dept is “IT”. Do the same using streams. Round 2: Diff between array and linked list ? Explain encapsulation and abstraction taking real life example. What is String and StringBuilder ? Why do we use them and when ? What is diff between atomicity and consistency in databases? How and where are foreign keys stored in many to many mapping ? Spring boot api designing - what all parameters and scenarios will you consider ? Microservices architecture How do you do security config in a spring boot application? Custom exceptions - how to create them ? Mockito - @InjectMock vs @Mock Coding question: Stream : 1. Find the highest occurring character in a string