Top Java Developer Interview Question And Answer

Here is the compiled list of the questions:

1. String API vs Collections API
2. Functional Interface
3. arrow function
4. java 1.7 vs 1.8 ( Java 8 Documentation )
5. the new feature in date Time API and what problem it solves
6. what is a Bean
7. What Is The Difference Between @Bean and @Component and When to Use What?
8. Solution for Scoped Bean Injection Problem in Spring
9. Factory vs abstract factory design pattern
10. strategy design pattern
11. isolation level in spring transaction
12. classloader in java
13. chain of responsibility principle
14. Exception propagation in Thread
15. cyclic barrier and countdown latches
16. semaphores
17. how to start two threads exactly same time
18. Hibernate cache level
19. procedure vs function
20. union vs unionAll in SQL
21. Functional Interface
22. what is optional and what is the use of it.
23. Immutable class and deep cloning
24. map vs flat map
25. sequential processing vs parallel processing
26. what is the use of Lambda expression
27. fork and join in java 8
28. custom array list
29. HashMap vs tree Map
30. why null is not allowed in TreeMap
31. java 8 new feature
32. java 8 filter student list age>5 or any first find record with given condition / get list of student name only.
33. io stream vs stream API
34. Integer i=100 j=100 i==j if x=1000 y =1000 i==j?
35. hibernate get vs load
36. spring internal work
37. class vs object lock
38. write a program for an object lock
39. type of scope in spring
40. session vs session factory
41. SQL joins
42. write rest API
43. multi-threading
44. Database
45. microservices
46. the three-ton object like singleton
47. facade decorated flyway  design pattern
48. spring IOC vs di
49. bean scope
50. @controller vs @Retcontroller vs @Service vs @Repository
51. what change in the collection in java 8
52. primary vs unique
53. trigger
54. HQL vs criteria query
55. ClassNotFoundException vs NoClassDefFoundError
56. Executer vs ExecuterService
57. @SpringBootApplication use
58. HashMap internal working – the algorithm used inside
59. HashSet internal working – the algorithm used inside
60. Joins?
61. Hibernate load vs get?
62. Hibernate cash type?
63. java type reference
64. java memory model
65. database constraint
66. Custom Exception
67. equal vs hash code contract java
68. IOC vs DI
69. BeanFactory vs ApplicationContext
70. Constructor vs setter autowire
71. Hibernate vs mybaites
72. count(1) is faster/optimized than count(*) because:
73.  count(*) has to iterate through all the columns,
74. But count(1) iterates through only one column.
75. count(*) vs count(1)
76. JDBC vs hibernate which performance is good?
77. so link list and array list are index base? performance? speed?

Java Concurrency related Topics

Java Concurrency is one of the most asked topics for java developers. 

• Synchronization utilities
  CountDownLatch in Java 
  CyclicBarrier in Java 
  Difference Between CountDownLatch And CyclicBarrier in Java
  Phaser in Java 
  Exchanger in Java 
  Semaphore in Java 
• Concurrent Collections
  ConcurrentHashMap in Java
  Difference Between HashMap And ConcurrentHashMap in Java
  CopyOnWriteArrayList in Java
  Difference Between ArrayList And CopyOnWriteArrayList in Java
  CopyOnWriteArraySet in Java
  ConcurrentSkipListMap in Java
  ConcurrentSkipListSet in Java
  ConcurrentLinkedQueue in Java
  ConcurrentLinkedDeque in Java
• BlockingQueue
  BlockingQueue in Java Concurrency
  ArrayBlockingQueue in Java Concurrency
  LinkedBlockingQueue in Java Concurrency
  PriorityBlockingQueue in Java Concurrency
  SynchronousQueue in Java
  DelayQueue in Java Concurrency
  LinkedTransferQueue in Java
• Locks
  ReentrantLock in Java Concurrency
  Difference Between ReentrantLock And Synchronized
  ReentrantReadWriteLock in Java
  StampedLock in Java
• BlockingDeque
  BlockingDeque in Java Concurrency
  LinkedBlockingDeque in Java
• Executors
  Callable And Future in Java Concurrency
  Difference Between Runnable And Callable in Java
  Executor And ExecutorService in Java Concurrency
  ThreadPoolExecutor – Java Thread Pooling With ExecutorService
  Java ScheduledThreadPoolExecutor – Task Scheduling in Java
  CompletableFuture in Java With Examples
  Atomic variables
  AtomicInteger in Java Concurrency
  AtomicLong in Java Concurrency
• Concurrency concepts
  Lock Striping in Java 
  Non-Blocking Algorithms
  Busy Spinning in Multi-Threading
  Blocking Methods in Java 
  Java Concurrency interview questions
  Java Concurrency Interview Questions And Answers.

Topic-wise Interview Questions List ( Link will come soon)

1. 1. Java OOP Interview Questions And Answers
   2. Core Java Basics Interview Questions And Answers
   3. Java String Interview Questions And Answers
   4. Java Exception Handling Interview Questions And Answers
   5. Java Multithreading Interview Questions And Answers
   6. Java Collections Interview Questions And Answers
   7. Java Concurrency Interview Questions And Answers
   8. Java Lambda Expressions Interview Questions And Answers
   9. Java Stream API Interview Questions And Answers

These are some compiled lists of Java Developer Interview Question And Answer

If you like to be a Java Full Stack Developer, please read our article Full-Stack: Your Guide to Becoming a Full-Stack Developer in 2021-22