JPA

Basic Concepts

1. What is JPA, and how does it differ from JDBC?
2. Explain the role of the Entity Manager in JPA.
3. What are the different types of persistence contexts in JPA?
4. Describe the lifecycle of an entity in JPA.
5. What is the purpose of the @Entity annotation?
6. How do you configure the JPA persistence unit in a Spring Boot application?
7. What are the different fetching strategies available in JPA?
8. Explain the difference between @Table and @Entity annotations.

Mapping and Annotations

9. How do you map a one-to-one relationship in JPA?
10. Explain the use of @JoinColumn in a many-to-one relationship.
11. What is the purpose of the @ManyToMany annotation, and how is it implemented?
12. How do you configure a bidirectional relationship in JPA?
13. Describe how to use @OneToMany and @ManyToOne annotations together.
14. What is the @MappedSuperclass annotation used for?
15. How does the @Embeddable annotation work, and what is its use case?
16. Explain how to use @ElementCollection for storing a collection of basic types.

Querying

17. What are JPQL and the differences between JPQL and SQL?
18. How do you create a custom JPQL query?
19. Explain the use of the @Query annotation in Spring Data JPA.
20. How do you use the Criteria API for dynamic queries in JPA?
21. Describe the EntityManager methods for querying entities.
22. How can you execute native SQL queries using JPA?
23. What is the purpose of @NamedQuery and how is it used?
24. How do you handle pagination and sorting with JPA?

Transactions and Concurrency

25. How does JPA handle transactions, and what are the different transaction types?
26. Explain the @Transactional annotation and its role in transaction management.
27. What are the different isolation levels available in JPA transactions?
28. Describe optimistic locking and how it is implemented in JPA.
29. How do you handle pessimistic locking in JPA?
30. What are the implications of using @Version for optimistic locking?
31. How can you configure transaction timeout in JPA?
32. Explain how JPA manages entity state transitions in a transaction.

Performance and Optimization

33. How do you optimize JPA performance for large datasets?
34. What is the purpose of the @Cacheable annotation, and how does it work?
35. How do you use query hints to improve JPA query performance?
36. Explain how you can use batch processing with JPA.
37. What are the differences between eager and lazy loading, and how do you manage them?
38. How do you handle N+1 select problems in JPA?
39. Describe how the @Fetch annotation can be used to control fetching strategies.
40. What are the advantages and disadvantages of using @BatchSize in JPA?

Advanced Topics

41. What are the differences between @EntityGraph and JOIN FETCH in JPA?
42. How do you implement soft deletes using JPA?
43. Explain the concept of multi-tenancy in JPA and how to configure it.
44. How do you use JPA with a non-relational database?
45. What are some common pitfalls when using JPA with complex object graphs?
46. Describe the use of @PostLoad, @PostPersist, @PostUpdate, and @PostRemove lifecycle callbacks.
47. How do you implement custom converters with JPA?
48. What is the role of the @Access annotation in JPA?

Error Handling and Troubleshooting

49. How do you handle and log exceptions in JPA?
50. What are common causes of LazyInitializationException, and how do you resolve them?
51. Describe how to diagnose and troubleshoot performance issues in JPA applications.
52. How do you handle entity not found exceptions in JPA?
53. What are some common JPA mapping errors and how can you avoid them?
54. How do you debug issues related to entity state transitions in JPA?
55. Explain how to address issues with entity identity and primary keys.
56. How do you deal with constraints and database schema mismatches in JPA?

Integration with Spring Boot

57. How do you configure JPA repositories in Spring Boot?
58. Explain how Spring Data JPA simplifies repository implementations.
59. What is the role of EntityManagerFactory and TransactionManager in Spring Boot with JPA?
60. How do you use Spring Boot’s automatic configuration for JPA?
61. Describe how you can define custom queries in a Spring Data JPA repository.
62. What is the purpose of @Repository annotation in Spring Data JPA?
63. How do you handle exception translation in Spring Data JPA?
64. What is the role of @EnableJpaRepositories in Spring Boot?

Schema Management

65. How does JPA handle schema generation and DDL operations?
66. Describe the use of @Table annotation and its attributes.
67. How do you customize table and column names using JPA annotations?
68. What is the role of schema-generation settings in JPA?
69. How do you use the @SecondaryTable annotation for multi-table mapping?
70. Explain the use of @AssociationOverride and @AttributeOverride annotations.
71. How do you manage schema evolution and database migrations with JPA?
72. What are the best practices for schema management in a production environment?

Miscellaneous

73. How do you handle large text fields or blobs in JPA?
74. What is the difference between @GeneratedValue strategies in JPA?
75. How do you map and use enums in JPA?
76. Explain the use of @Transient and @PostConstruct annotations in JPA.
77. How do you implement and use inheritance with JPA?
78. What are the advantages of using JPA over plain JDBC for data access?
79. How do you perform database migrations with JPA?
80. Describe how you would use JPA with Spring Boot’s integration testing support.

Best Practices and Patterns

81. What are some best practices for using JPA in high-performance applications?
82. How do you handle database connections and resource management with JPA?
83. What patterns and practices should be followed when using JPA with complex domain models?
84. How can you ensure data consistency and integrity when using JPA?
85. What are some common design patterns for optimizing JPA applications?
86. How do you handle concurrency control and conflicts in JPA?
87. What are some strategies for caching entities in JPA?
88. How do you use DTOs (Data Transfer Objects) with JPA?

Migration and Evolution

89. How do you handle schema migrations with JPA in a continuous integration/continuous deployment (CI/CD) pipeline?
90. Explain the use of tools like Liquibase or Flyway for schema management with JPA.
91. How do you manage and handle legacy database schemas with JPA?
92. What are some strategies for evolving JPA-based applications over time?
93. How do you migrate from one JPA implementation to another?
94. What are the considerations for upgrading JPA versions in an existing application?
95. How do you handle changes in database schemas when using JPA?
96. What are the implications of changing entity mappings in a production environment?

Real-World Scenarios

97. How would you approach refactoring an existing JPA application to improve performance?
98. Describe a scenario where you had to debug a complex JPA issue and how you resolved it.
99. How do you handle multi-tenant data access in a JPA application?
100. Describe a complex data migration project involving JPA and how you managed it.