Java Interview Questions for SDET

Hi , Sharing core Java interview questions and answer on the Finance domain and mostly on big Investment banks. Many of these Java interview questions are asked on JP Morgan, Morgan Stanley, Barclays, or Goldman Sachs.

In all questions ,try to give answers by giving examples of finance domain(Like banking system, loan ,fraud)anks mostly asked core Java interview questions from multi-threading, collection, serialization, coding and OOPS design principles.

1. Explain Lambda expressions in Java 8 — Why its used
2. Explain static Constructor if its possible
3. Explain private Constructor and its usage(Hint-Singelton)
4. Explain private/protected/public inheritence and their various combinations like — is a variable can be private+Final or Public+Final(when it will be)
5. Multiple inheritence in Java (Other than interface)
6. Generics in Hashmap(Is it possible to have Hashmap without any generics in left side while initialization) — if not -will it give compilation error?
7. Explain String immutable (Reverse and count of characters without string function)
8. Explain Hashmap principle(if same keys/values will be given)-then is linkedlist will be made?
9. Is Hashmap threadsafe? How it can be made
10. Where does equals() and hashCode() method comes in the picture during the get() operation
11. What is the difference between creating String as new() and literal
12. What’s wrong using HashMap in the multi-threaded environment? When get() method go to the infinite loop
13. Does not overriding hashCode() method has any performance implication
14. Data visualization tools and examples
15. SQL penetration test and type of attacks?Any example
16. Array vs Arraylist
17. Sorting with use of collections and without collection
18. Read data from excel sheet (wrt to data not rows and columns)-APACHE POI
19. Does all property of Immutable Object needs to be final
20. When do you override hashCode() and equals()?
21. Comparison of objects of 2 classes in Java
22. Memory management (heap memory ,Garbage collections)
23. Grep commands with combination of copying a command.
24. Difference between atomic, volatile and synchronized in Java?
25. Challenge faced in application development /automation