Introduction
This post will have most important interview questions which used to ask in most of the reputed companies like Google, Amazon, Net App, Wells Fargo etc.
We are just adding Questions to this post and the technical reader will post the answers using comments sections.
We will provide all questions with a proper explanation later in the separate post and will link to this post.
Hope reader will enjoy the post and helps us to get the proper answers.
Note: Most of the questions asked during real interviews.
Please follow below section for list of questions –
Q1. Implement BTree – Add, Delete and Search?
Ans:
Q2. Explained and Implement Double Liked List?
Q3. If there would be Database lock then what will you do to release the lock?
Q4. How to analyze Heap Dump and Thread Dump?
Q5. Can you please explanans application server and its usages?
Q6. What will you do if SQL Query wrote in the application causing slowness?
Q7. What are the specifications to develop APIs?
Q8. What are REST and SOAP? can you explain the usage and circumstances in which we use them?
Q9. What is the problem that you solved in your project recently?
Q10. Can you please design class diagram for the multithreaded environment?
Q11. Can you please write Singleton design pattern implementation?
Q12. What is method overriding?
Q13. What is method overloading?
Q14. What are all design principles?
Q15. What is the difference between synchronized block and synchronized method?
Q16. What is the advantage of Concurrent HashMap?
Q17. How will load balancing work in microservices architecture?
Q18. What is Executor Framework? How is it advantageous?
Q19. What is Read-Write Lock? Does ConcurrentHashMap in Java Use The ReadWrite Lock?
Q20. How to Make an Object Immutable in Java? Why Should You Make an Object Immutable?
Q21. Which Design Patterns have You Used in Your Java Project?
Q22. Do you know about Open Closed Design Principle or Liskov Substitution Principle?
Q23. How does ConcurrentHashMap achieve its Scalability?
Q24. How do you share an object between threads? or How to pass an object from one thread to another?
Q25. Difference between String, StringBuffer and StringBuilder in Java?
Q26. Difference between extends Thread vs implements Runnable in Java?
Q27. Difference between Runnable and Callable interface in Java?
Q28. Difference between ArrayList and LinkedList in Java?
Q29. What is a difference between wait and notify in Java?
Q30. Difference between HashMap and Hashtable in Java?
Q31. Difference between TreeSet and TreeMap in Java?
Q32. Difference between Serializable and Externalizable in Java?
Q33. Difference between abstract class and interface?
Q34. Can you override static method in Java?
Q35. What is difference between synchronize and concurrent Collection in Java?
Q36. What is difference between Overloading and Overriding in Java?
Q37. What is ClassLoader in Java?
Q38. What best practices you follow while doing Exception handling in Java ?
Q39. Have you written your own custom Exception in Java? How do you do that?
Q40. Have you faced OutOfMemoryError in Java? How did you solved that?
Q41. What are the different methods of session management in servlets?
Q42. What is JDBC Driver?
Q43. What is the difference between execute, executeQuery, executeUpdate?
Q44. What is the purpose of serialization?
Q45. What are immutable objects in Java? Can we change the value of an immutable object?
Q46. What is comparator and comparable?
Q47. How concurrentHashMap works internally?
Q48. How to restrict cloning in SingleTon Object?
Q49. Can you please explain Observer pattern with an example?
Q50. What are the new features in JDK1.8?
Q51. What are composition and aggregation?
Q52. What are composition and inheritance?
Q53. What is microservices architecture?
Q54. How to build a dictionary like application?
Q55. How to build an Amazon like concurrent website?
Q56. What is difference between String, StringBuffer and StringBuilder? When to use them?
Q57. Difference between Volatile and transient?
Q58. Program. Write a code for following.
for string=1462 calculate from right most to left in this manner 2+(6*2)+4+(1*2) [where every II, Iv, vi, .. should be multiplied by 2 and the sum should be divided by10 if quotient is 0 then print true otherwise false
1462=2+(6*2)+4+(1*2) = 20%10=0 (true)
1764526=6+(2*2)+5+(4*2)+6+(7*2)+1=44%10!=0(false)
Q59. In Java, what is the difference between final, finally, and finalize?
Q60. What is multithreaded programming? What is a deadlock?
Q61. What is the difference between Throw and Throws in Java Exception Handling?
Q62. Describe your major projects in recent history and what you yourself were challenged with and accomplished?
Q63. Given a scenario to architect a mobile/web app to get cricket info i.e. Ball By Ball updates, an average of batsman and average of bowlers.
Q64. How can you convert any object to JsonObject?
Q65. How can you convert any data to HashMap in java8?
Q66. What is the difference between queue and Topic in Kafta and JMS?
Q67. What is the difference between broker and Topic in Kafta?
Q68. How can you create RestClient with SpringBoot and without SpringBoot?
Q69. Scale the given scenario further again to get all info about all bowlers in the world for given period of time?
Hint- Use concurrentHashMap and use proper POJO to stores all bowlers data. Use multithreaded environment with executor framework to update and delete/hold concurrent data about all sorts of bowler data. your POJO should have dependency injected one with another. One for all kind of bowlers info. Another for the match by match info POJO with details POJO injected into that.
Q70. Explain JMS?
Q71. What is the difference between equals and hashcode?
Q72. What is SpringBoot annotation?
Q73. Pros and Cors of SpringBoot?
Q74. How to do exception handling in SprigBoot?
Q75. What happened to request when microservice is down?
Q76. Write a code to implement put method in the HashMap.
Q77. Write a code to implement connection pool/thread Pool in java.
Q78. What is thread safety?
Q79. What is the relationship between Volatile, Synchronize and Thread Safety?
Q80. How Does Serialization work at the time of inheritance and composition?
Q81. Write a code to implement BTree?
Q82. How does Blocking Queue work?
Q83. How can we write operation in hibernate?
Q84. How are we implementing a transaction in hibernate?
Q85. Explain limitation of autowiring in spring?
Q86. What is the difference between controller and rest controller in rest web services?
Q87. Explain Bean Lifecycle in Spring?
Q88. What are all types of UML diagram is there?
Q89. How are you write a Eureka service in Spring Boot?
Q90. How can you do performance tuning in Spring?
Q91. How can you draw asynchronous call in sequence diagram?
Q92. How can you call store proc in java?
Q93. What are all new features in java8?
Q94. Write a program when multiple threads are accessing n number of files and search a specific keyword. Write and optimize it to extream cases.
Q95. What is Stream API in Java8?
Q96. When do you want to use Kafta over any other technology?
Q97. Why concurrent hashMap introduced and in which version of java?
Q98. Explain internal implementation of executor framework?
Q99. Why wait(), notify() and notifyAll() in Object class?
Q100. Why is wait method associated with Object class?
Q101. How many elements can we add to an ArrayList?
Q102. What are the features of Rest API?
Q103. When to use Put and Post and why?
Q104. What is restful API default caching Mechanism?
Q105. Explain memory leak and how to handle it?
Q106. What is PermGen Memory?
Q107. Explain the memory management and GC Process?
Q108. Different between Map and HashMap and explain in detail?
Q109. What is spring boot?
Q110. How to use authentication and authorization in Spring boot?
Q111. How to do performance tuning for image loading from database?
Q112. What is the difference between SAX and DOM parser?
Q113. How JWT token handles multiple requests?
Q114. How to read 5th last node of a single linked list?
Q115. What is the performance caution you will consider while designing application DAO Layer?
Q116. How executor service handle parallel processing?
Q117. Hibernate stores first label of cache in memory or in a browser?
Q118. How react handle Jwt token?
Q119. How to write native SQL using spring data JPA?
Q120. You have millions of records and wanted to store in the database, which approach or methodology can be efficient?
Q121. Find the max element from the stack using one method call?
Q122. Check palindrome by using one loop?
Q123. Write an algorithm to generate a random number and call another object to print the random number?
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