#Postgresql

Last updated    - V6 (05-Oct-2025)

Key Concepts

Topic	SubTopics	Basic	Intermediate	Advanced	Expert
Introduction & Basics	Overview, Features, Editions, Comparison with other RDBMS	✅
Installation & Configuration	System Requirements, Installation (Linux/Windows), Configuration Files	✅	✅
Databases & Schemas	Creating Databases, Schemas, Default Settings, Search Paths	✅	✅
Tables & Data Types	Creating Tables, Column Types, Constraints, Serial/UUID, JSON/JSONB	✅	✅
Primary & Foreign Keys	PK, FK, Referential Integrity, Cascading Rules	✅	✅
Indexes	B-Tree, Hash, GIN, GiST, BRIN, Partial, Expression Indexes		✅	✅
Views	Simple Views, Materialized Views, Security, Refresh Strategies	✅	✅	✅
Stored Procedures & Functions	PL/pgSQL, Language Functions, Parameters, RETURNS	✅	✅	✅
Triggers	BEFORE/AFTER, INSTEAD OF, Row-Level, Statement-Level		✅	✅
Transactions	BEGIN/COMMIT/ROLLBACK, ACID, Isolation Levels, Savepoints	✅	✅	✅
Locks & Concurrency	Row-Level Locks, Table Locks, Deadlocks, Advisory Locks		✅	✅
Constraints	NOT NULL, UNIQUE, CHECK, EXCLUSION, DEFAULT	✅	✅
Normalization & Design	1NF, 2NF, 3NF, Denormalization, ERD	✅	✅
Querying	SELECT, JOINs, WHERE, GROUP BY, HAVING, ORDER BY, DISTINCT	✅	✅	✅
Advanced Queries	CTEs, Window Functions, Ranking, Aggregates, JSON Queries		✅	✅
Performance Tuning	EXPLAIN/EXPLAIN ANALYZE, Index Tuning, Query Optimization		✅	✅
Partitioning	Table Partitioning, Inheritance, Declarative Partitioning		✅	✅
Backup & Restore	pg_dump, pg_restore, Base Backups, PITR (Point-in-Time Recovery)	✅	✅	✅
Replication & High Availability	Streaming Replication, Logical Replication, Hot Standby, Failover		✅	✅	✅
Security	Roles, Users, Permissions, Row-Level Security, Authentication	✅	✅	✅	✅
Monitoring & Maintenance	pg_stat views, Logs, AutoVacuum, Maintenance Tasks		✅	✅
Extensions & Plugins	PostGIS, pg_partman, citext, Custom Extensions		✅	✅	✅
Foreign Data Wrappers (FDW)	postgres_fdw, oracle_fdw, MongoDB FDW, Configuration		✅	✅	✅
Advanced Features	JSONB Indexing, Full-Text Search, Materialized Views, GIN Index		✅	✅	✅
Cloud & Scaling	Amazon RDS, Aurora, GCP Cloud SQL, Citus, Sharding Strategies			✅	✅

Interview question

Basic Level

1. What is PostgreSQL and how is it different from other RDBMS like MySQL or Oracle?
2. What are the main features of PostgreSQL?
3. Explain the architecture of PostgreSQL.
4. How do you install PostgreSQL on Linux and Windows?
5. What is psql in PostgreSQL?
6. How do you create a new database in PostgreSQL?
7. How do you list all databases in PostgreSQL?
8. What are schemas in PostgreSQL?
9. How do you connect to a PostgreSQL database using psql?
10. Explain the difference between CHAR, VARCHAR, and TEXT in PostgreSQL.
11. How do you create a table in PostgreSQL?
12. What are the different data types available in PostgreSQL?
13. How do you insert data into a PostgreSQL table?
14. How do you update and delete data in PostgreSQL?
15. What are sequences in PostgreSQL?
16. How do you create a sequence in PostgreSQL?
17. What is a primary key in PostgreSQL?
18. How do you define a foreign key in PostgreSQL?
19. What are indexes in PostgreSQL?
20. How do you create an index in PostgreSQL?
21. What is the difference between DELETE and TRUNCATE?
22. What is the purpose of the RETURNING clause in PostgreSQL?
23. How do you enable case-insensitive search in PostgreSQL?
24. Explain the difference between NULL and an empty string.
25. How do you backup and restore a PostgreSQL database?

---

Intermediate Level

1. What are PostgreSQL system catalogs?
2. How does PostgreSQL handle transactions?
3. Explain the concept of MVCC (Multi-Version Concurrency Control).
4. What is the difference between COMMIT and ROLLBACK?
5. How do you implement foreign key constraints with cascading actions?
6. What is a materialized view in PostgreSQL?
7. How do you refresh a materialized view?
8. Explain the difference between VIEW and MATERIALIZED VIEW.
9. What are window functions in PostgreSQL?
10. How do you use ROW_NUMBER(), RANK(), and DENSE_RANK()?
11. What are PostgreSQL extensions? Give examples.
12. What is the pgAdmin tool used for?
13. How do you monitor queries in PostgreSQL?
14. What is the EXPLAIN command used for?
15. How do you optimize queries in PostgreSQL?
16. Explain the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.
17. How do you implement recursive queries in PostgreSQL?
18. What is the difference between NOW() and CURRENT_DATE?
19. Explain COALESCE() function in PostgreSQL.
20. How do you use JSON and JSONB data types in PostgreSQL?
21. How do you create and query an array column in PostgreSQL?
22. What are PostgreSQL operators for pattern matching?
23. Explain IS DISTINCT FROM operator in PostgreSQL.
24. How do you grant and revoke privileges in PostgreSQL?
25. What is the role of pg_hba.conf?

---

Advanced Level

1. Explain Write-Ahead Logging (WAL) in PostgreSQL.
2. How does PostgreSQL ensure data consistency?
3. What are the different types of indexes in PostgreSQL?
4. When should you use GIN vs BTREE indexes?
5. Explain Partial Indexes in PostgreSQL.
6. What is a covering index in PostgreSQL?
7. How do you implement full-text search in PostgreSQL?
8. Explain the difference between TO_CHAR() and TO_DATE().
9. How does PostgreSQL handle concurrency and locking?
10. What are advisory locks in PostgreSQL?
11. How does VACUUM work in PostgreSQL?
12. What is the difference between VACUUM and VACUUM FULL?
13. What is ANALYZE used for?
14. How does PostgreSQL query planner work?
15. What are parallel queries in PostgreSQL?
16. Explain logical vs physical replication.
17. How do you configure replication in PostgreSQL?
18. What are hot standby servers in PostgreSQL?
19. Explain Point-In-Time Recovery (PITR) in PostgreSQL.
20. How do you implement partitioning in PostgreSQL?
21. Explain the difference between range and list partitioning.
22. What is a foreign data wrapper (FDW)?
23. How do you connect PostgreSQL with other databases using FDW?
24. What are stored procedures in PostgreSQL?
25. How do you write PL/pgSQL functions?

---

Expert Level

1. Explain PostgreSQL?s process architecture (postmaster, background workers, autovacuum).
2. How do you handle deadlocks in PostgreSQL?
3. What strategies can be used for PostgreSQL performance tuning?
4. How do you tune work_mem, shared_buffers, and effective_cache_size?
5. What are PostgreSQL tablespaces?
6. How do you create and use a tablespace?
7. What is sharding in PostgreSQL? How can it be implemented?
8. How does PostgreSQL differ from distributed databases like CockroachDB or Citus?
9. What is the difference between synchronous and asynchronous replication?
10. How do you set up synchronous replication?
11. How do you monitor replication lag in PostgreSQL?
12. How do you implement high availability (HA) in PostgreSQL?
13. Explain connection pooling in PostgreSQL.
14. What is PgBouncer and how is it used?
15. How do you implement partition pruning in PostgreSQL?
16. Explain JIT (Just-In-Time) compilation in PostgreSQL.
17. How do you debug performance issues in PostgreSQL queries?
18. What are generated columns in PostgreSQL?
19. How do you implement Row-Level Security (RLS)?
20. How do you use event triggers in PostgreSQL?
21. Explain logical decoding in PostgreSQL.
22. What is WAL archiving and how is it configured?
23. How does PostgreSQL handle large objects (LOBs)?
24. What are common PostgreSQL anti-patterns to avoid?
25. Compare PostgreSQL with NoSQL databases in terms of scalability and flexibility.

Related Topics

#CoreJava_08

Last updated    - V4 (16-Sep-2025)

Key Concepts

Topic	Sub-Topics	Basic	Intermediate	Advanced	Expert
Lambda Expressions	Syntax, Scope, Variable capture, Method references, Constructor references	✔️	✔️	✔️	✔️
Functional Interfaces	Predicate, Consumer, Supplier, Function, BiFunction, UnaryOperator, BinaryOperator, Custom FI	✔️	✔️	✔️	✔️
Stream API - Basics	Creating streams, map(), filter(), forEach(), count(), collect()	✔️	✔️
Stream API - Intermediate	distinct(), sorted(), limit(), skip(), peek(), Optional + Streams		✔️	✔️
Stream API - Advanced	reduce(), flatMap(), groupingBy(), partitioningBy(), joining(), summarizing, parallelStream()		✔️	✔️	✔️
Stream API - Expert	Custom collectors, Stream performance tuning, Spliterator, Lazy evaluation, Infinite streams			✔️	✔️
Optional Class	of(), ofNullable(), empty(), isPresent(), ifPresent(), orElse(), orElseGet(), orElseThrow()	✔️	✔️
Date and Time API (java.time)	LocalDate, LocalTime, LocalDateTime, Instant, ZoneId, OffsetDateTime, Period, Duration	✔️	✔️	✔️
Date and Time Formatting	DateTimeFormatter, Custom patterns, Parsing, Timezone conversions		✔️	✔️
Default & Static Methods in Interfaces	Default methods, Static methods, Diamond problem, Multiple inheritance resolution	✔️	✔️	✔️	✔️
CompletableFuture & Concurrency	supplyAsync(), runAsync(), thenApply(), thenAccept(), thenCombine(), allOf(), anyOf()		✔️	✔️	✔️
Asynchronous Programming	Exception handling in CompletableFuture, Non-blocking computations, Chaining futures			✔️	✔️
Nashorn JavaScript Engine	Script execution, Bind Java Objects, Invoke Java methods, External JS files, Performance		✔️	✔️
Collections Enhancements	forEach(), removeIf(), replaceAll(), computeIfAbsent(), computeIfPresent(), merge()	✔️	✔️	✔️
Map API Improvements	getOrDefault(), putIfAbsent(), replaceAll(), compute(), replace(), new traversal APIs	✔️	✔️	✔️
StringJoiner & Collectors	joining(), delimiters, prefix & suffix, Collectors.toList(), toSet(), toMap()	✔️	✔️	✔️
Base64 Encoding/Decoding	Basic, URL, MIME encoding & decoding	✔️	✔️
Arrays Enhancements	parallelSort(), setAll(), parallelPrefix(), Arrays.stream()	✔️	✔️	✔️
Annotations (Java 8)	@FunctionalInterface, @Repeatable, Type Annotations, @Target, @Retention	✔️	✔️	✔️
Method References	Reference to static methods, instance methods, constructors	✔️	✔️	✔️
Parallel Programming	Parallel streams, ForkJoinPool, Performance considerations		✔️	✔️	✔️
Spliterator API	tryAdvance(), forEachRemaining(), characteristics(), estimateSize(), parallel iteration			✔️	✔️
Security & Java 8	SecureRandom with streams, Optional null-safety, Immutable Date-Time API	✔️	✔️	✔️	✔️
Miscellaneous Utilities	Objects.requireNonNullElse(), Files.lines(), Instant.now(), Comparator.comparing()	✔️	✔️	✔️	✔️
Performance Tuning	Streams vs loops, Parallel stream overhead, Memory considerations			✔️	✔️
Testing with Java 8	Testing Lambdas, Streams, and CompletableFuture, Mocking functional interfaces		✔️	✔️	✔️

Interview question

1. Lambda Expressions (25 Questions)

1. What is a lambda expression in Java 8?
2. Why were lambda expressions introduced in Java?
3. Explain the syntax of a lambda expression with an example.
4. How does a lambda expression differ from an anonymous class?
5. Can lambda expressions access local variables from the enclosing scope?
6. What is variable capture in lambdas?
7. What are the restrictions on accessing variables inside lambdas?
8. How does this behave inside a lambda expression?
9. Can lambdas be recursive? How?
10. How do you use lambdas with functional interfaces?
11. What is the target type of a lambda expression?
12. Can you overload methods with lambda parameters?
13. How does type inference work in lambda expressions?
14. Can lambdas throw checked exceptions?
15. Can lambdas have multiple return statements?
16. Difference between -> and :: operators in Java 8.
17. What are the advantages of using lambdas?
18. How are lambdas internally implemented in Java?
19. Can lambdas be serialized?
20. How do you debug lambda expressions?
21. Can you assign a lambda to a variable?
22. How do lambdas improve iteration over collections?
23. Give an example of using a lambda with Runnable.
24. How does the compiler determine the type of a lambda?
25. What are some real-world use cases of lambdas?

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2. Functional Interfaces (25 Questions)

1. What is a functional interface in Java 8?
2. Explain the @FunctionalInterface annotation.
3. Give 5 examples of built-in functional interfaces.
4. Difference between Predicate and Function.
5. Difference between Consumer and Supplier.
6. What is a UnaryOperator? Example?
7. What is a BinaryOperator? Example?
8. How do you chain functional interfaces like Predicate and Function?
9. Can functional interfaces have default methods?
10. Can functional interfaces have static methods?
11. Can a functional interface extend another interface?
12. What happens if you declare two abstract methods in a functional interface?
13. How does type inference work with functional interfaces?
14. Can a functional interface be generic?
15. What are primitive specializations of functional interfaces?
16. Can functional interfaces throw exceptions?
17. How do you implement a custom functional interface?
18. How do you use method references with functional interfaces?
19. What is the difference between apply() in Function and test() in Predicate?
20. Can functional interfaces be Serializable?
21. What is the role of java.util.function package?
22. When should you explicitly use @FunctionalInterface?
23. Can functional interfaces override equals() and hashCode()?
24. How do functional interfaces enable functional programming in Java?
25. Real-world use case of functional interfaces?

---

3. Stream API Basics (25 Questions)

1. What is the Stream API in Java 8?
2. Difference between a Collection and a Stream?
3. How do you create a stream from a list?
4. What are intermediate operations in streams?
5. What are terminal operations in streams?
6. Explain lazy evaluation in streams.
7. Difference between map() and flatMap().
8. What does the filter() operation do?
9. How do you sort a stream?
10. What is the use of forEach() in streams?
11. Difference between sequential and parallel streams.
12. How do you collect stream results into a list?
13. How do you collect stream results into a set?
14. What is the reduce() operation in streams?
15. Difference between findFirst() and findAny().
16. How do you use limit() and skip() in streams?
17. How does distinct() work in streams?
18. Explain peek() and its use case.
19. Can you reuse a stream after a terminal operation?
20. How do you create an infinite stream?
21. How does performance differ between loops and streams?
22. Can streams work on primitive types?
23. How do you debug a stream pipeline?
24. How does short-circuiting work in streams?
25. Real-world use case of streams?

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4. Optional Class (25 Questions)

1. What is Optional in Java 8?
2. Why was Optional introduced?
3. How do you create an Optional object?
4. Difference between Optional.of() and Optional.ofNullable().
5. What does Optional.empty() return?
6. How do you check if a value is present in Optional?
7. Difference between isPresent() and ifPresent().
8. How do you provide a default value with Optional?
9. Difference between orElse() and orElseGet().
10. Difference between orElse() and orElseThrow().
11. How do you transform values inside Optional using map()?
12. Difference between map() and flatMap() in Optional.
13. How do you filter values in Optional?
14. Can Optional itself be null?
15. Can Optional be used for method parameters?
16. What are drawbacks of using Optional excessively?
17. Can Optional be serialized?
18. How do you return Optional from repository methods?
19. Can you use Optional with Streams?
20. How do you combine multiple Optionals?
21. Is Optional thread-safe?
22. Can Optional hold collections?
23. What is the difference between Optional in Java and Maybe in other FP languages?
24. Should Optional be used in DTOs?
25. Real-world use cases of Optional?

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5. Date and Time API (25 Questions)

1. What is the new Date/Time API in Java 8?
2. Why was it introduced when we already had Date and Calendar?
3. What is LocalDate?
4. What is LocalTime?
5. What is LocalDateTime?
6. What is ZonedDateTime?
7. How do you parse and format dates in Java 8?
8. Difference between DateTimeFormatter and SimpleDateFormat?
9. What is Period in Java 8?
10. What is Duration in Java 8?
11. How do you calculate the difference between two dates?
12. How do you add or subtract days from a date?
13. How do you check if a year is a leap year?
14. How do you handle time zones in Java 8?
15. Difference between Instant and LocalDateTime.
16. How do you convert between old Date and new DateTime API?
17. What is Clock in Date/Time API?
18. What is TemporalAdjuster?
19. What is TemporalUnit?
20. How do you get the start and end of a day?
21. What is the difference between OffsetDateTime and ZonedDateTime?
22. How do you compare two dates in Java 8?
23. Can LocalDate represent time?
24. Can LocalTime represent date?
25. Real-world use cases of Date/Time API?

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6. Default & Static Methods in Interfaces (25 Questions)

1. What are default methods in Java 8?
2. Why were default methods introduced?
3. Can interfaces have method implementations in Java 8?
4. How do you define a default method?
5. Can a class override a default method?
6. What happens if two interfaces have the same default method?
7. How do you resolve conflicts in multiple inheritance with default methods?
8. Can interfaces have static methods?
9. How do you call a static method in an interface?
10. Can default methods be abstract?
11. Can interfaces have private methods in Java 8?
12. How do default methods impact backward compatibility?
13. Can constructors be default methods?
14. How do you use default methods with collections?
15. Can default methods call abstract methods?
16. Can default methods be overridden by subclasses?
17. What is the difference between default methods and abstract classes?
18. Can default methods be synchronized?
19. Can default methods throw exceptions?
20. Can default methods call other default methods?
21. Are static methods inherited in interfaces?
22. Can you override static methods from interfaces?
23. Can static methods in interfaces be private?
24. Real-world use case of default methods?
25. Real-world use case of static methods in interfaces?

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7. CompletableFuture & Concurrency (25 Questions)

1. What is CompletableFuture in Java 8?
2. How is CompletableFuture different from Future?
3. How do you create a CompletableFuture?
4. How do you run asynchronous tasks with CompletableFuture?
5. Difference between runAsync() and supplyAsync().
6. What is thenApply() in CompletableFuture?
7. What is thenAccept()?
8. What is thenRun()?
9. Difference between thenCompose() and thenCombine().
10. How do you handle exceptions in CompletableFuture?
11. What is exceptionally() method?
12. What is handle() method?
13. How do you combine multiple CompletableFutures?
14. Difference between allOf() and anyOf().
15. How do you cancel a CompletableFuture?
16. How do you block and get the result?
17. What is join() in CompletableFuture?
18. Difference between join() and get().
19. How do you implement timeouts in CompletableFuture?
20. Is CompletableFuture thread-safe?
21. How do you use custom thread pools with CompletableFuture?
22. Difference between synchronous and asynchronous callbacks?
23. How does CompletableFuture improve parallelism?
24. How do you test CompletableFutures?
25. Real-world use cases of CompletableFuture?

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8. Collections & Map Enhancements (25 Questions)

1. What enhancements were made to collections in Java 8?
2. What is the forEach() method in collections?
3. How do you use removeIf()?
4. What is the replaceAll() method?
5. What is the sort() method in List?
6. How do you use computeIfAbsent() in Map?
7. How do you use computeIfPresent()?
8. How do you use compute()?
9. What is merge() in Map?
10. How do you use getOrDefault() in Map?
11. What is putIfAbsent()?
12. What is replace() in Map?
13. How do you use forEach() in Map?
14. Difference between entrySet() iteration and forEach().
15. How do you sort a Map by values?
16. Can you use streams with collections directly?
17. What is Spliterator?
18. How is Spliterator different from Iterator?
19. What is trySplit() in Spliterator?
20. How do you estimate size in Spliterator?
21. What is the ORDERED characteristic in Spliterator?
22. What is the CONCURRENT characteristic?
23. What is the DISTINCT characteristic?
24. What is the IMMUTABLE characteristic?
25. Real-world use case of collection enhancements?

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9. Streams Advanced (25 Questions)

1. What are parallel streams?
2. How do you create a parallel stream?
3. Difference between sequential and parallel stream performance?
4. What are the pitfalls of parallel streams?
5. How does fork-join framework work with parallel streams?
6. What is Collectors.groupingBy()?
7. What is Collectors.partitioningBy()?
8. Difference between groupingBy() and partitioningBy().
9. What is Collectors.mapping()?
10. How do you join strings using Collectors.joining()?
11. How do you count elements using Collectors.counting()?
12. What is Collectors.summarizingInt()?
13. What is Collectors.averagingDouble()?
14. What is Collectors.reducing()?
15. What is a custom collector?
16. How do you implement your own collector?
17. What is a downstream collector?
18. Difference between reduce() and collect().
19. Can streams be infinite?
20. How do you use Stream.iterate()?
21. How do you use Stream.generate()?
22. What is flatMapToInt()?
23. What is boxed() in streams?
24. What is parallelism level in parallel streams?
25. Best practices for using advanced streams?

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10. Miscellaneous Java 8 Features (25 Questions)

1. What is Nashorn in Java 8?
2. How do you execute JavaScript with Nashorn?
3. What is StringJoiner in Java 8?
4. How do you join strings with a delimiter using StringJoiner?
5. What enhancements were made to String in Java 8?
6. What is the new Base64 API in Java 8?
7. Difference between Encoder and Decoder in Base64.
8. How do you encode and decode a string with Base64?
9. What enhancements were made to Arrays in Java 8?
10. How do you sort an array with a custom comparator in Java 8?
11. What is Arrays.parallelSort()?
12. What is SplittableRandom?
13. How is SplittableRandom different from Random?
14. What enhancements were made to Comparator in Java 8?
15. How do you use comparing() method in Comparator?
16. How do you use thenComparing()?
17. What are annotation enhancements in Java 8?
18. What is repeating annotations?
19. What is type annotation in Java 8?
20. How do you declare type-use annotations?
21. Can annotations be applied to generics in Java 8?
22. Can annotations be inherited in Java 8?
23. What is method parameter reflection in Java 8?
24. What are compact profiles?
25. Summary of miscellaneous features introduced in Java 8?

Related Topics

Lambda Expressions

Functional Interfaces

Stream API

#Azure

Last updated    - V6 (18-Sep-2025)

Key Concepts

Topic	Sub-Topics	Basic	Intermediate	Advanced	Expert
Compute	Virtual Machines, VM Scale Sets, App Services, Azure Functions, Logic Apps	✅	✅	✅	✅
Storage	Blob Storage, Table Storage, Queue Storage, File Storage, Data Lake Gen2	✅	✅	✅	✅
Networking	VNet, Subnets, NSG, Load Balancer, Application Gateway, Front Door, ExpressRoute, VPN Gateway, Traffic Manager	✅	✅	✅	✅
Databases	Azure SQL, Cosmos DB, Synapse, PostgreSQL/MySQL, Managed Instance	✅	✅	✅	✅
Identity & Security	Azure AD, RBAC, MFA, Conditional Access, PIM, Key Vault, Azure Policy	✅	✅	✅	✅
Monitoring & Management	Azure Monitor, Log Analytics, Application Insights, Azure Advisor, Cost Management, Blueprints	✅	✅	✅	✅
Containers & Kubernetes	AKS, ACR, Container Instances, Helm, Service Mesh	✅	✅	✅	✅
Integration Services	Event Grid, Event Hub, Service Bus, API Management	✅	✅	✅	✅
DevOps & Automation	Azure DevOps, Pipelines, Repos, Artifacts, Boards, ARM Templates, Bicep, Automation	✅	✅	✅	✅
AI & ML	Cognitive Services, Azure ML, Databricks, Cognitive Search	✅	✅	✅	✅
Data & Analytics	Data Factory, Synapse, Databricks, HDInsight, Power BI Integration	✅	✅	✅	✅
Hybrid & Multi-Cloud	Azure Arc, Azure Stack, Lighthouse	✅	✅	✅	✅
Migration & DR	Azure Migrate, Site Recovery, Database Migration Service	✅	✅	✅	✅
IoT & Edge	IoT Hub, IoT Edge, Digital Twins, Stream Analytics, Private MEC	✅	✅	✅	✅
Security & Compliance	Security Center, Defender for Cloud, Sentinel, Confidential Computing	✅	✅	✅	✅
Enterprise Governance	Blueprints, Policy, Cost Management, FinOps	✅	✅	✅	✅
Big Data & HPC	HDInsight, Databricks, HPC Clusters	✅	✅	✅	✅
Media & Content Delivery	Media Services, CDN	✅	✅	✅	✅
Blockchain	Azure Blockchain Service, Confidential Ledger	✅	✅	✅	✅
Specialized Workloads	SAP on Azure, HPC, AI Supercomputing	✅	✅	✅	✅

Interview question

Basic Level

1. What is Microsoft Azure?
2. What are the main advantages of using Azure?
3. Explain the difference between IaaS, PaaS, and SaaS.
4. What are Azure Regions and Availability Zones?
5. What is Azure Resource Manager (ARM)?
6. What is an Azure Subscription?
7. What is the difference between Azure Tenant and Subscription?
8. What is Azure Virtual Machine (VM)?
9. What is the difference between VM Scale Sets and Availability Sets?
10. What are Azure App Services?
11. What is Azure Functions?
12. What is Azure Logic Apps?
13. What is Azure Blob Storage?
14. What are the storage tiers in Azure?
15. Difference between Blob, File, Queue, and Table storage.
16. What is an Azure Virtual Network (VNet)?
17. What are Network Security Groups (NSGs)?
18. What is Azure Load Balancer?
19. What is Application Gateway?
20. What is ExpressRoute?
21. What is Azure SQL Database?
22. What is the difference between SQL Database and Managed Instance?
23. What is Cosmos DB?
24. What is Azure Synapse Analytics?
25. What is Azure Active Directory (AAD)?
26. What is the difference between Azure AD and AD DS?
27. What is Role-Based Access Control (RBAC)?
28. What is Multi-Factor Authentication (MFA) in Azure?
29. What is Azure Key Vault?
30. What is Azure Monitor?
31. What is Log Analytics in Azure?
32. What is Application Insights?
33. What is Azure Advisor?
34. What is Azure Kubernetes Service (AKS)?
35. What is Azure Container Registry (ACR)?
36. What are Azure Container Instances?
37. What is Azure Event Grid?
38. What is Azure Service Bus?
39. What is Azure DevOps?
40. What are Pipelines in Azure DevOps?
41. What are Repos and Artifacts in Azure DevOps?
42. What are Boards in Azure DevOps?
43. What is Cognitive Services in Azure?
44. What is Azure Machine Learning?
45. What is Azure Databricks?
46. What is Azure Data Factory?
47. What is Azure Arc?
48. What is Azure Stack HCI?
49. What is Azure Site Recovery?
50. What is Azure Migrate?

---

Intermediate Level

1. How does Azure VM Scale Sets provide scalability?
2. What are Availability Zones vs Availability Sets?
3. How do you secure Azure Virtual Machines?
4. How do you configure Azure Bastion?
5. What is Azure Application Gateway with WAF?
6. How does Azure Front Door work?
7. What is the difference between Azure Load Balancer and Front Door?
8. What is a VNet Peering?
9. Difference between VPN Gateway and ExpressRoute.
10. What is Private Link in Azure?
11. What is a Service Endpoint in Azure Networking?
12. How does Cosmos DB handle partitioning?
13. What are consistency levels in Cosmos DB?
14. How does Cosmos DB provide multi-region replication?
15. What is Synapse Analytics used for?
16. What is PolyBase in Synapse?
17. What is Azure Data Lake Storage Gen2?
18. What are Managed Identities in Azure?
19. What is Conditional Access in Azure AD?
20. What is Privileged Identity Management (PIM)?
21. How does Azure Key Vault integrate with applications?
22. What are Diagnostic Settings in Azure Monitor?
23. How does Log Analytics query language (KQL) work?
24. How does Application Insights help in distributed tracing?
25. What is Azure Policy?
26. What is the difference between Azure Monitor and Azure Security Center?
27. What is Azure Defender for Cloud?
28. What is AKS node pool?
29. How do you scale AKS clusters?
30. How do Helm charts work in AKS?
31. What is Azure Functions Consumption Plan?
32. What are Durable Functions in Azure?
33. How does Event Grid integrate with Logic Apps?
34. What is the difference between Event Hub and Service Bus?
35. How does Azure DevOps integrate with GitHub Actions?
36. What are YAML pipelines in Azure DevOps?
37. What are Deployment Groups?
38. What are Artifacts in Azure DevOps used for?
39. What is Azure Cognitive Search?
40. What are Prebuilt Models in Cognitive Services?
41. How does Azure Machine Learning handle model deployment?
42. What is Databricks Delta Lake?
43. How does Azure Data Factory perform ETL?
44. What is Azure Lighthouse?
45. How does Azure Arc help with hybrid management?
46. How does Site Recovery work for DR scenarios?
47. What is Database Migration Service (DMS)?
48. What is Azure Blueprints?
49. How does Cost Management + Billing work?
50. What is Azure Pricing Calculator?

---

Advanced Level

1. How to design a hub-and-spoke network topology in Azure?
2. How does Azure Firewall work?
3. Difference between Firewall and NSG.
4. How do you design a global VNet architecture?
5. How to implement ExpressRoute Global Reach?
6. How does Azure Traffic Manager work?
7. How do you configure load balancing across regions?
8. How does Cosmos DB scale elastically?
9. How to tune indexing policies in Cosmos DB?
10. How to design for strong consistency vs eventual consistency?
11. How to optimize Synapse pipelines for big data?
12. How to integrate Synapse with Power BI?
13. How does Data Lake Gen2 handle hierarchical namespace?
14. How to secure storage accounts with Private Endpoints?
15. How to rotate keys in Key Vault automatically?
16. How to implement Conditional Access policies for external users?
17. How does Azure Sentinel integrate with Security Center?
18. How to configure Just-In-Time (JIT) access to VMs?
19. How to enforce least privilege in RBAC at scale?
20. How to configure Azure Policy for compliance enforcement?
21. How to deploy multi-region AKS clusters?
22. How to secure AKS clusters using Azure AD integration?
23. How to configure network policies in AKS?
24. How does Azure Functions integrate with VNETs?
25. How to optimize cold start in Functions?
26. What is an Event-driven serverless architecture with Event Grid?
27. How does Durable Functions support fan-out/fan-in?
28. How to design enterprise DevOps pipelines in Azure?
29. How to implement approvals in multi-stage pipelines?
30. How to use service connections securely in Azure DevOps?
31. How does Azure ML pipeline work?
32. How to monitor ML models in production with Azure Monitor?
33. How to scale Databricks clusters dynamically?
34. How to optimize Data Factory performance for large ETL jobs?
35. How to configure monitoring with Application Insights at scale?
36. How to use Azure Blueprints for governance?
37. How to implement hybrid Kubernetes clusters with Azure Arc?
38. How does Lighthouse manage multiple tenants?
39. How to configure advanced disaster recovery with Site Recovery?
40. How to migrate enterprise SAP workloads to Azure?
41. How to integrate Azure AD with on-prem Active Directory?
42. How to implement passwordless authentication in Azure?
43. How to use Azure Privileged Identity Management at scale?
44. How to handle data residency and compliance in Azure?
45. How to secure multi-cloud with Azure Security Center?
46. How to enforce compliance using Azure Defender?
47. How to design FinOps practices in Azure?
48. How to implement tagging governance?
49. How to use Managed Grafana in Azure Monitor?
50. How to implement custom log ingestion into Log Analytics?

---

Expert Level

1. How to design enterprise-scale landing zones in Azure?
2. How to enforce governance using Azure Policy at enterprise scale?
3. How to design Zero Trust architecture in Azure?
4. How to implement enterprise-wide RBAC strategy?
5. How to secure multi-tenant SaaS applications in Azure?
6. How to manage hybrid cloud with Azure Arc across multiple clouds?
7. How to configure cross-region traffic routing with Traffic Manager + Front Door?
8. How to implement Azure ExpressRoute with MPLS?
9. How to integrate Azure Stack with on-prem data centers?
10. How to manage sovereignty and compliance with Azure Government cloud?
11. How to secure highly regulated workloads (HIPAA, GDPR) in Azure?
12. How to design Cosmos DB for financial-grade workloads?
13. How to implement multi-master replication in Cosmos DB?
14. How to optimize Synapse Analytics for enterprise data warehouses?
15. How to implement Data Mesh with Azure Data Lake + Synapse?
16. How to implement cross-region failover with Azure SQL Hyperscale?
17. How to optimize ML lifecycle with MLOps in Azure?
18. How to integrate Databricks with Synapse for real-time analytics?
19. How to implement advanced data governance in Azure Purview?
20. How to build enterprise-scale IoT solutions with Azure IoT Hub?
21. How to integrate IoT Hub with Event Grid and Stream Analytics?
22. How to secure IoT devices with Azure Defender for IoT?
23. How to build digital twins using Azure Digital Twins?
24. How to implement edge computing with Azure IoT Edge?
25. How to build 5G-enabled solutions with Azure Private MEC?
26. How to integrate Azure with AWS and GCP in a multi-cloud strategy?
27. How to manage cost governance across multi-cloud with Azure Cost Management?
28. How to use Lighthouse for managed service providers (MSPs)?
29. How to enforce enterprise-wide tagging compliance?
30. How to implement chaos engineering in Azure?
31. How to implement automated incident response with Logic Apps?
32. How to build self-healing systems with Azure Monitor + Automation?
33. How to design HA/DR for SAP on Azure?
34. How to secure Kubernetes workloads across multi-region AKS?
35. How to implement service mesh (Istio/Linkerd) in AKS?
36. How to secure CI/CD pipelines with Azure DevOps + Key Vault?
37. How to implement GitOps in AKS using Flux/ArgoCD?
38. How to implement enterprise blockchain solutions with Azure Blockchain Service?
39. How to design HPC clusters in Azure for research workloads?
40. How to optimize large-scale video streaming with Azure Media Services?
41. How to design AI at scale using Azure Cognitive Services?
42. How to build enterprise knowledge mining solutions with Cognitive Search?
43. How to integrate Azure Synapse with Power Platform at scale?
44. How to secure enterprise ML pipelines with Responsible AI?
45. How to use Azure Arc-enabled Kubernetes for hybrid governance?
46. How to implement DevSecOps pipelines in Azure?
47. How to enforce compliance with Azure Policy + Defender across 1000+ subscriptions?
48. How to implement disaster recovery for multi-cloud apps?
49. How to run confidential computing workloads with Azure Confidential VMs?
50. How to architect for 99.999% availability on Azure?

Related Topics

Azure_DevOps

#GraphQL

Last updated    - V6 (03-Oct-2025)

Key Concepts

Topic	SubTopic	Basic ✅	Intermediate ✅	Advanced ✅	Expert ✅
Introduction	What is GraphQL, Features, Benefits, Use cases	✅	✅	✅	✅
GraphQL vs REST	Differences, Advantages, Limitations, When to use	✅	✅	✅	✅
Queries	Basics, Nested queries, Arguments, Aliases	✅	✅	✅	✅
Mutations	Create, Update, Delete operations, Input types	✅	✅	✅	✅
Subscriptions	Real-time updates, WebSockets, Implementation		✅	✅	✅
Schema	Types, Fields, Query type, Mutation type, Subscription type	✅	✅	✅	✅
Types	Scalar types, Object types, Enum, Interface, Union	✅	✅	✅	✅
Resolvers	Resolver functions, Arguments, Context, Parent object	✅	✅	✅	✅
Variables	Input variables, Default values, Variable types	✅	✅	✅	✅
Directives	@include, @skip, @deprecated, Custom directives	✅	✅	✅	✅
Error Handling	GraphQL errors, Error codes, Custom errors		✅	✅	✅
Authentication & Authorization	JWT, OAuth, Role-based access, Field-level security		✅	✅	✅
Performance Optimization	Query batching, Caching, DataLoader, Complexity analysis			✅	✅
Tooling & Ecosystem	Apollo, Relay, GraphiQL, GraphQL Playground	✅	✅	✅	✅
Best Practices	Schema design, Versioning, Pagination, Security	✅	✅	✅	✅

Interview question

Basic

1. What is GraphQL?
2. Who developed GraphQL?
3. What are the main benefits of GraphQL over REST?
4. What is a GraphQL schema?
5. What are queries in GraphQL?
6. What are mutations in GraphQL?
7. What are subscriptions in GraphQL?
8. What is a resolver in GraphQL?
9. What is the difference between query and mutation?
10. What are GraphQL types?
11. What are scalar types in GraphQL?
12. What are enums in GraphQL?
13. What are lists in GraphQL?
14. What are non-null types in GraphQL?
15. What is introspection in GraphQL?
16. What is a fragment in GraphQL?
17. What are directives in GraphQL?
18. What is the default HTTP method for GraphQL requests?
19. How is GraphQL strongly typed?
20. What is the difference between GraphQL and SQL?
21. Can GraphQL work without a database?
22. What is the role of __typename in GraphQL?
23. What is batching in GraphQL?
24. What is the purpose of GraphQL variables?
25. What are the limitations of GraphQL?

---

Intermediate

1. What is the role of GraphQL schema definition language (SDL)?
2. How do you define custom scalar types in GraphQL?
3. Explain input types in GraphQL.
4. What are unions in GraphQL?
5. What are interfaces in GraphQL?
6. How do you validate GraphQL queries?
7. How does GraphQL handle versioning?
8. What are the best practices for naming in GraphQL schema?
9. What is query complexity analysis?
10. How does GraphQL handle over-fetching and under-fetching?
11. What are nested resolvers?
12. What is the N+1 problem in GraphQL?
13. How can you solve the N+1 problem in GraphQL?
14. What is DataLoader in GraphQL?
15. How does GraphQL handle error reporting?
16. What are partial responses in GraphQL?
17. How does GraphQL differ from gRPC?
18. How do you use variables with fragments in GraphQL?
19. How does caching work in GraphQL?
20. What is persisted queries in GraphQL?
21. What is GraphQL Playground?
22. What is Apollo Server?
23. What is Relay in GraphQL?
24. How do GraphQL subscriptions work with WebSockets?
25. What are the security concerns in GraphQL?

---

Advanced

1. What are GraphQL Federation and schema stitching?
2. What is Apollo Federation?
3. What is the difference between schema stitching and federation?
4. What is GraphQL Gateway?
5. How do you implement authentication in GraphQL?
6. How do you implement authorization in GraphQL?
7. What are GraphQL directives and how do you create custom ones?
8. How do you handle file uploads in GraphQL?
9. What is GraphQL mesh?
10. What are GraphQL unions vs interfaces?
11. How do you implement batching in GraphQL resolvers?
12. What are best practices for designing GraphQL mutations?
13. How do you handle pagination in GraphQL?
14. What are Relay-style pagination and connections?
15. How do you handle rate limiting in GraphQL APIs?
16. What is query depth limiting in GraphQL?
17. How does GraphQL handle subscriptions at scale?
18. How does GraphQL integrate with microservices?
19. How do you monitor GraphQL performance?
20. How do you trace GraphQL queries in production?
21. What is schema federation in Apollo?
22. What are schema delegation techniques in GraphQL?
23. How do you modularize large GraphQL schemas?
24. What is GraphQL schema stitching middleware?
25. What are GraphQL schema directives for logging and tracing?

---

Expert

1. How do you secure GraphQL APIs against DoS attacks?
2. What is query cost analysis in GraphQL?
3. How do you handle caching in GraphQL at scale?
4. How do you integrate GraphQL with REST APIs?
5. How do you integrate GraphQL with gRPC?
6. How do you optimize GraphQL queries in production?
7. What are advanced DataLoader patterns?
8. How do you implement GraphQL schema federation in microservices architecture?
9. How do you version GraphQL schemas in large organizations?
10. How does GraphQL fit into Event-Driven Architectures (EDA)?
11. How do you monitor and log GraphQL errors?
12. How do you integrate GraphQL with Kafka?
13. How do you handle real-time updates in GraphQL at scale?
14. What is Apollo Gateway architecture?
15. How do you build resilient GraphQL APIs?
16. What are GraphQL SDL limitations and solutions?
17. How do you implement GraphQL authorization at field level?
18. How do you manage breaking changes in GraphQL APIs?
19. What are GraphQL best practices for microfrontends?
20. How do you design GraphQL APIs for large-scale enterprise systems?
21. What is GraphQL-over-HTTP vs GraphQL-over-WebSockets?
22. How do you handle federation across multiple teams in GraphQL?
23. What are common GraphQL anti-patterns?
24. What is the future of GraphQL in API design?
25. Compare GraphQL, REST, gRPC, and OData for enterprise use cases.

Related Topics

#SonarQube

Last updated    - V6 (05-Oct-2025)

Key Concepts

Topic	SubTopics	Basic	Intermediate	Advanced	Expert
Introduction & Basics	Overview of SonarQube, Purpose, Features, Editions (Community vs Enterprise)	✅
Installation & Setup	System Requirements, Installation (Windows/Linux/Docker), Initial Configuration	✅	✅
Architecture	Components (Server, Database, Scanner, Web Interface), Data Flow	✅	✅
Projects & Sources	Creating Projects, Analyzing Source Code, Project Structure	✅	✅
Scanners	SonarQube Scanner CLI, Maven/Gradle Integration, Jenkins/GitHub Actions		✅	✅
Quality Profiles	Default Profiles, Creating Custom Profiles, Rule Customization		✅	✅
Quality Gates	Default Quality Gate, Custom Gates, Conditions, Thresholds		✅	✅
Rules & Issues	Types of Issues (Bug, Vulnerability, Code Smell), Rule Management, Suppression	✅	✅	✅
Dashboards & Reports	Project Dashboard, Portfolio Dashboard, PDF/Email Reports	✅	✅	✅
Metrics & Measures	Code Coverage, Duplications, Complexity, Maintainability Index	✅	✅	✅
Security	OWASP Top 10, SAST (Static App Sec Testing), Security Hotspots		✅	✅	✅
User Management	Users, Groups, Roles, Permissions	✅	✅
Integrations	CI/CD (Jenkins, GitLab, Azure DevOps), SCM (Git, SVN), IDE Plugins		✅	✅	✅
Database Management	Supported Databases (PostgreSQL, Oracle, MS SQL), Backup & Restore		✅	✅
Advanced Configuration	Global Settings, Project Settings, Branch Analysis, Pull Request Decoration			✅
APIs	Web API, Automating Analysis, Integrating Custom Scripts			✅	✅
Multi-Language Support	Java, C#, Python, JavaScript, C/C++, Custom Language Plugins	✅	✅	✅	✅
Performance & Scaling	Tuning, Horizontal Scaling, Enterprise Setup, Monitoring			✅	✅
Governance & Compliance	Licensing, Portfolio Management, Regulatory Compliance			✅	✅
DevOps & Automation	Pipeline as Code, Automated Quality Gates, Shift-Left Testing		✅	✅	✅
Plugins & Marketplace	Installing Plugins, Managing Updates, Developing Custom Plugins		✅	✅	✅
Troubleshooting & Logs	Common Errors, Debugging Analysis Failures, Log Files	✅	✅	✅
Upgrade & Migration	Upgrading Versions, Migrating Databases, Zero Downtime Upgrades			✅	✅
Best Practices	Rule Tuning, Team Adoption, Reducing Technical Debt		✅	✅	✅
Future & Roadmap	New Features, AI in Code Analysis, Market Trends				✅

Interview question

📘 Basic Level

1. What is SonarQube and why is it used?
2. What are the key features of SonarQube?
3. Explain the difference between SonarQube Community and Enterprise editions.
4. What is a SonarQube Scanner?
5. What is a Quality Gate in SonarQube?
6. What is a Quality Profile in SonarQube?
7. What types of issues can SonarQube detect?
8. What is the difference between a bug, vulnerability, and code smell?
9. How do you install SonarQube on Linux/Windows?
10. What database backends are supported by SonarQube?
11. How do you create a new project in SonarQube?
12. What is the default port for SonarQube?
13. How do you run a SonarQube scan on a Java project?
14. What is SonarLint, and how is it related to SonarQube?
15. What is the difference between SonarScanner CLI and Maven/Gradle plugins?
16. How do you view the analysis report in SonarQube?
17. What is the role of the sonar-project.properties file?
18. How do you set up users and permissions in SonarQube?
19. How do you assign a Quality Profile to a project?
20. What are SonarQube rules?
21. How do you suppress false positives in SonarQube?
22. What is meant by code coverage in SonarQube?
23. What programming languages are supported in the Community edition?
24. What is meant by ?technical debt? in SonarQube?
25. What is the purpose of SonarQube dashboards?

---

📗 Intermediate Level

1. How do you integrate SonarQube with Jenkins?
2. How do you configure GitHub pull request decoration in SonarQube?
3. How do you integrate SonarQube with GitLab CI/CD?
4. What is branch analysis in SonarQube?
5. How do you configure SonarQube for multi-language projects?
6. What are hotspots in SonarQube?
7. How do you create a custom Quality Gate?
8. What are conditions in Quality Gates?
9. What is the role of Quality Profiles in enforcing coding standards?
10. How do you install and manage SonarQube plugins?
11. How do you configure email notifications in SonarQube?
12. How do you monitor project metrics such as coverage and duplications?
13. What are the default metrics tracked by SonarQube?
14. How do you perform incremental analysis with SonarQube?
15. How does SonarQube integrate with Azure DevOps pipelines?
16. What are portfolio dashboards in SonarQube Enterprise edition?
17. How do you migrate SonarQube to a new server?
18. How do you back up SonarQube?
19. What is SonarQube?s role in DevOps pipelines?
20. How do you enforce mandatory Quality Gates in CI/CD?
21. How do you configure role-based access control (RBAC) in SonarQube?
22. How do you use the Web API in SonarQube?
23. What are the differences between SonarLint and SonarQube?
24. How do you analyze a project with Gradle in SonarQube?
25. How do you handle authentication in SonarQube?

---

📕 Advanced Level

1. How does SonarQube measure maintainability?
2. Explain the architecture of SonarQube.
3. What are the roles of Elasticsearch in SonarQube?
4. How do you tune SonarQube performance for large codebases?
5. What are custom rules in SonarQube?
6. How do you write a custom rule for Java in SonarQube?
7. How do you configure advanced Quality Profiles?
8. How do you perform zero-downtime upgrades of SonarQube?
9. How do you handle branch analysis in Community vs Developer edition?
10. What are duplications in SonarQube, and how are they detected?
11. How do you configure SonarQube with PostgreSQL?
12. How do you enforce OWASP Top 10 checks in SonarQube?
13. How does SonarQube detect SQL injection vulnerabilities?
14. How do you configure LDAP or SAML authentication in SonarQube?
15. What are portfolio management features in SonarQube Enterprise?
16. How do you implement governance in SonarQube?
17. What are leak periods in SonarQube?
18. How do you integrate SonarQube with Bitbucket pipelines?
19. How do you manage multi-tenant projects in SonarQube?
20. How do you configure project tags and categories in SonarQube?
21. How do you automate SonarQube analysis in a pipeline?
22. How do you customize dashboards in SonarQube?
23. How do you manage rule inheritance in Quality Profiles?
24. What is differential analysis in SonarQube?
25. How do you monitor SonarQube with Prometheus and Grafana?

---

📓 Expert Level

1. How do you design a scalable SonarQube architecture for enterprise?
2. How do you configure horizontal scaling in SonarQube?
3. How do you secure SonarQube against OWASP vulnerabilities?
4. How do you optimize SonarQube for thousands of concurrent scans?
5. What are best practices for managing Quality Gates across 500+ projects?
6. How do you configure multi-region SonarQube deployments?
7. How do you develop a custom SonarQube plugin?
8. What are the internals of SonarQube?s rule engine?
9. How do you implement advanced CI/CD with SonarQube and Kubernetes?
10. How do you integrate SonarQube with service mesh environments?
11. How do you perform root-cause analysis on SonarQube performance issues?
12. How do you configure enterprise-grade RBAC across hundreds of teams?
13. How do you manage SonarQube in hybrid cloud setups?
14. How do you integrate SonarQube with enterprise SSO providers?
15. How do you secure secrets in SonarQube pipelines?
16. How do you configure compliance reports for financial regulations?
17. How do you monitor SonarQube logs at scale using ELK?
18. How do you implement zero trust security in SonarQube?
19. How do you manage petabyte-scale code analysis in SonarQube?
20. What are challenges in migrating from Fortify/Checkmarx to SonarQube?
21. How do you integrate SonarQube with AI/ML pipelines?
22. What is the future of SonarQube in the DevSecOps ecosystem?
23. How do you optimize rule sets for microservices architectures?
24. How do you manage SonarQube for 1000+ developers?
25. How do you enforce enterprise-wide technical debt reduction with SonarQube?

---

Related Topics

#Hibernate

Last updated    - V6 (04-Oct-2025)

Key Concepts

Topic	SubTopics	Basic	Intermediate	Advanced	Expert
Introduction	ORM Concepts, Benefits of Hibernate, JPA vs Hibernate	✅
Configuration	hibernate.cfg.xml, Properties, Annotations, Persistence.xml	✅	✅
Session & SessionFactory	Session lifecycle, openSession vs getCurrentSession, Thread safety	✅	✅
Mapping Basics	Entity mapping, @Entity, @Table, @Id, @GeneratedValue	✅
Relationships	One-to-One, One-to-Many, Many-to-One, Many-to-Many	✅	✅
Inheritance	Single Table, Joined, Table per Class strategies		✅	✅
HQL & JPQL	Queries, Named Queries, Parameters, Pagination		✅	✅
Criteria API	Restrictions, Projections, Order, Pagination		✅	✅
Native SQL	SQL Queries, Mapping results, Stored Procedures		✅	✅
Caching	First-level, Second-level, Query cache, Cache providers (Ehcache, Infinispan)			✅	✅
Transactions	Transaction API, ACID properties, Declarative Transactions	✅	✅	✅
Fetching	Lazy vs Eager loading, N+1 problem, Fetch Joins		✅	✅	✅
Batch Processing	Bulk updates, Batch size, StatelessSession			✅	✅
Performance Tuning	Query optimization, Fetch strategies, Cache tuning			✅	✅
Event System	Interceptors, EventListeners, Entity lifecycle callbacks			✅	✅
Validation	JSR-303 Bean Validation, @Valid, @NotNull	✅	✅
Spring Integration	Spring Boot + Hibernate, Transaction Management		✅	✅	✅
Advanced Mappings	Composite keys, @EmbeddedId, @MapsId, Join tables			✅	✅
Multi-tenancy	Database-level, Schema-level, Discriminator strategies				✅
Hibernate & JPA 2.x+	CriteriaBuilder, Metamodel API, TypedQuery		✅	✅	✅
Concurrency	Optimistic vs Pessimistic locking, Versioning			✅	✅
Migration & Versioning	Flyway, Liquibase with Hibernate, Schema evolution			✅	✅
Native Integration	Hibernate with NoSQL (OGM), Search (Lucene/Elasticsearch)				✅
Testing	In-memory DBs (H2), Unit & Integration Testing	✅	✅	✅

Interview question

Basic

1. What is Hibernate?
2. Difference between Hibernate and JDBC?
3. What are the advantages of Hibernate ORM?
4. What is JPA and how is it related to Hibernate?
5. Explain ORM in simple terms.
6. What is the role of hibernate.cfg.xml?
7. What is the use of SessionFactory?
8. What is the difference between Session and SessionFactory?
9. Explain the lifecycle of a Hibernate Session.
10. What are persistent objects in Hibernate?
11. What is the difference between transient, persistent, and detached objects?
12. Explain the role of @Entity annotation.
13. How do you map a table to a class in Hibernate?
14. What is @Id and @GeneratedValue annotation used for?
15. How do you configure database connection in Hibernate?
16. What is Hibernate Dialect?
17. Explain HQL (Hibernate Query Language).
18. What is the difference between HQL and SQL?
19. How do you perform CRUD operations in Hibernate?
20. What is the default fetching strategy in Hibernate?
21. Difference between get() and load() methods?
22. What are named queries in Hibernate?
23. Explain the role of @Table annotation.
24. What is the use of hibernate.properties file?
25. Explain the difference between save(), persist(), and saveOrUpdate().

---

Intermediate

1. What are the different types of entity mapping in Hibernate?
2. How do you implement one-to-one mapping in Hibernate?
3. How do you implement one-to-many mapping in Hibernate?
4. How do you implement many-to-many mapping in Hibernate?
5. Explain cascading in Hibernate.
6. What is lazy loading in Hibernate?
7. Difference between lazy and eager fetching?
8. What is the N+1 select problem?
9. How to solve N+1 problem in Hibernate?
10. What are embedded objects in Hibernate?
11. Explain inheritance mapping strategies in Hibernate.
12. Difference between Single Table and Joined strategy?
13. How do you configure table per class hierarchy?
14. What is the role of @Inheritance annotation?
15. Explain the role of @MappedSuperclass.
16. What are Hibernate annotations used for composite keys?
17. How do you handle versioning in Hibernate?
18. Explain optimistic and pessimistic locking.
19. What is Hibernate Criteria API?
20. Difference between HQL and Criteria API?
21. What are projections in Criteria API?
22. How do you add restrictions in Criteria API?
23. What is the use of CriteriaBuilder in JPA?
24. How do you perform pagination in Hibernate?
25. Difference between Query, TypedQuery, and CriteriaQuery?

---

Advanced

1. What is the role of Session.flush()?
2. What is the difference between flush() and commit()?
3. Explain clear() and evict() methods.
4. How do you detach an entity in Hibernate?
5. What is the use of merge() in Hibernate?
6. What is the difference between merge() and update()?
7. What is the first-level cache in Hibernate?
8. What is the second-level cache in Hibernate?
9. What cache providers can be used with Hibernate?
10. What is query-level cache in Hibernate?
11. How do you configure Ehcache in Hibernate?
12. Explain Hibernate?s integration with Spring.
13. What is the role of LocalSessionFactoryBean in Spring?
14. How do you configure transaction management in Spring + Hibernate?
15. Difference between programmatic and declarative transactions?
16. What are Interceptors in Hibernate?
17. Difference between Interceptor and EventListener?
18. Explain entity lifecycle events in Hibernate.
19. How do you use Hibernate with stored procedures?
20. How do you map native SQL queries in Hibernate?
21. What are named native queries?
22. How do you log SQL queries in Hibernate?
23. Explain batch processing in Hibernate.
24. How do you configure batch size in Hibernate?
25. What is StatelessSession in Hibernate?

---

Expert

1. What are best practices for Hibernate performance tuning?
2. How do you optimize Hibernate for large datasets?
3. How do you use Fetch Joins in Hibernate?
4. Explain DTO projection using Hibernate.
5. What is Hibernate Validator and how is it used?
6. What is JSR-303 Bean Validation in Hibernate?
7. How do you configure custom validators in Hibernate?
8. What is a proxy object in Hibernate?
9. What are bytecode enhancement techniques in Hibernate?
10. Explain dirty checking in Hibernate.
11. How does Hibernate detect changes in entities?
12. What is Hibernate Envers?
13. How do you implement auditing in Hibernate?
14. Explain multi-tenancy support in Hibernate.
15. Difference between schema, database, and discriminator-based multi-tenancy?
16. How does Hibernate integrate with NoSQL databases?
17. What is Hibernate OGM?
18. Explain Hibernate Search and its use cases.
19. How does Hibernate integrate with Elasticsearch?
20. Explain polyglot persistence with Hibernate.
21. How do you handle migration and versioning with Hibernate?
22. How do you integrate Hibernate with Flyway or Liquibase?
23. How do you debug Hibernate performance issues?
24. How does Hibernate differ from JPA, MyBatis, and EclipseLink?
25. Future of Hibernate: How does it fit into modern microservices and cloud-native architectures?

Related Topics

#Apache_Spark

Last updated    - V6 (17-Sep-2025)

Key Concepts

Topic	Sub-Topics	Basic	Intermediate	Advanced	Expert
Introduction	What is Spark, Features, Spark vs Hadoop, Use cases	✅	✅
Architecture	Spark Components, Driver, Executor, Cluster Manager, DAG, Jobs, Stages, Tasks	✅	✅	✅	✅
RDDs	Resilient Distributed Datasets, Transformations, Actions, Caching, Persistence	✅	✅	✅	✅
DataFrames & Datasets	Creation, Schema, Operations, Optimizations, Catalyst Engine	✅	✅	✅	✅
Spark SQL	SQL Queries, Data Sources, Temporary Views, Performance Tuning	✅	✅	✅	✅
Spark Streaming	DStreams, Structured Streaming, Window Operations, Checkpointing	✅	✅	✅	✅
Spark MLlib	Machine Learning APIs, Pipelines, Models, Feature Engineering	✅	✅	✅	✅
Spark GraphX	Graphs, Pregel API, Graph Algorithms		✅	✅	✅
Spark Core APIs	RDD API, Transformations, Actions, Accumulators, Broadcast Variables	✅	✅	✅	✅
Performance Tuning	Partitioning, Caching, Shuffling, Join optimizations, Resource tuning		✅	✅	✅
Cluster Management	Standalone, YARN, Mesos, Kubernetes, Resource Allocation	✅	✅	✅	✅
Debugging & Monitoring	Spark UI, Logs, Event Timeline, Metrics, Executors monitoring	✅	✅	✅	✅
Fault Tolerance	Lineage, Task Retry, Checkpointing, Speculative Execution	✅	✅	✅	✅
Advanced Features	Custom Partitioner, User-defined functions, Structured Streaming triggers		✅	✅	✅
Integration	Hive, HDFS, Kafka, Cassandra, Parquet, ORC, JDBC	✅	✅	✅	✅

Interview question

1. Introduction & Basics

1. What is Apache Spark and what are its main features?
2. How does Spark differ from Hadoop MapReduce?
3. What are the core components of Spark?
4. What is SparkContext?
5. What is the role of a Driver in Spark?
6. What is an Executor in Spark?
7. What is a DAG in Spark?
8. What are jobs, stages, and tasks in Spark?
9. What are the key use cases of Spark?
10. What is the difference between batch processing and stream processing in Spark?

---

2. Architecture

1. Explain the Spark architecture.
2. What are the main cluster managers supported by Spark?
3. How does Spark schedule tasks?
4. How does Spark handle fault tolerance?
5. What is the role of the DAG scheduler?
6. How are RDDs distributed across the cluster?
7. How does Spark handle data locality?
8. What is the role of the Task Scheduler?
9. How does Spark communicate between Driver and Executors?
10. What is the Spark UI and how is it used?

---

3. RDDs

1. What is an RDD in Spark?
2. How do you create RDDs?
3. What are the main transformations in RDDs?
4. What are the main actions in RDDs?
5. How does Spark achieve fault tolerance in RDDs?
6. What is the difference between narrow and wide transformations?
7. How do caching and persistence work in RDDs?
8. What is a lineage graph?
9. What is the difference between map() and flatMap()?
10. How do you perform joins on RDDs?

---

4. DataFrames & Datasets

1. What is a DataFrame in Spark?
2. How do DataFrames differ from RDDs?
3. How do you create a DataFrame?
4. What are Datasets in Spark?
5. How do Datasets differ from DataFrames?
6. How does Spark infer schema automatically?
7. How do you perform filtering and aggregations on DataFrames?
8. What is the Catalyst optimizer?
9. How do you register a temporary view for SQL queries?
10. How do you handle missing data in DataFrames?

---

5. Spark SQL

1. How do you execute SQL queries in Spark?
2. How do you connect Spark to Hive?
3. What are the different data sources supported by Spark SQL?
4. How do you create external and managed tables?
5. What is partitioning in Spark SQL?
6. How do you optimize joins in Spark SQL?
7. How do you cache tables in Spark SQL?
8. How does Spark SQL handle schema evolution?
9. How do you use UDFs in Spark SQL?
10. How do you monitor query performance in Spark SQL?

---

6. Spark Streaming

1. What is Spark Streaming?
2. What are DStreams?
3. How does Structured Streaming differ from DStreams?
4. What are window operations in Spark Streaming?
5. What is checkpointing and why is it used?
6. How do you handle late data in streaming?
7. What are triggers in Structured Streaming?
8. How do you integrate Kafka with Spark Streaming?
9. How do you monitor streaming jobs?
10. How do you ensure exactly-once semantics in streaming?

---

7. Spark MLlib

1. What is MLlib?
2. What are the main features of MLlib?
3. How do you create a machine learning pipeline in Spark?
4. How do you handle feature engineering in Spark MLlib?
5. What are transformers and estimators?
6. How do you perform model evaluation?
7. How do you handle classification tasks in Spark MLlib?
8. How do you handle regression tasks?
9. How do you save and load models?
10. How do you tune hyperparameters in Spark MLlib?

---

8. Spark GraphX

1. What is GraphX?
2. How do you represent graphs in Spark?
3. What are vertices and edges?
4. What is the Pregel API?
5. How do you compute PageRank in GraphX?
6. How do you find connected components?
7. How do you implement graph algorithms using GraphX?
8. How do you persist graph data?
9. How do you visualize graphs from Spark?
10. What are practical use cases of GraphX?

---

9. Performance Tuning

1. How do you optimize partitioning in Spark?
2. How do you reduce shuffle operations?
3. How do you cache and persist data for performance?
4. How do you tune memory and executor configurations?
5. What are broadcast variables and how are they used?
6. How do accumulators work in Spark?
7. How do you optimize joins in Spark?
8. How do you handle skewed data?
9. How do you monitor and profile Spark jobs?
10. How do you use Tungsten optimization?

---

10. Cluster Management

1. What are the different deployment modes in Spark?
2. How do you run Spark in Standalone mode?
3. How do you run Spark on YARN?
4. How do you run Spark on Mesos?
5. How do you run Spark on Kubernetes?
6. How do you configure Spark executors and cores?
7. How do you handle dynamic allocation?
8. How do you manage resources in a multi-tenant cluster?
9. How do you submit a Spark job?
10. How do you handle failures in Spark clusters?

Related Topics

#Spring_Cloud

Last updated    - V6 (15-Oct-2025)

Key Concepts

Topic	Sub-Topics	Basic	Intermediate	Advanced	Expert
Introduction	Microservices, Advantages, Spring Cloud overview	✅	✅
Configuration Management	Spring Cloud Config Server, Config Client, Encryption/Decryption	✅	✅	✅	✅
Service Discovery	Eureka Server, Eureka Client, Registration, Discovery	✅	✅	✅	✅
Load Balancing	Ribbon, Spring Cloud LoadBalancer, Client-side vs Server-side	✅	✅	✅	✅
API Gateway	Zuul, Spring Cloud Gateway, Routing, Filters	✅	✅	✅	✅
Declarative REST Clients	Feign, @FeignClient, Custom configurations	✅	✅	✅	✅
Circuit Breaker	Hystrix, Resilience4j, Fallback methods		✅	✅	✅
Distributed Tracing	Sleuth, Zipkin, Trace context propagation		✅	✅	✅
Messaging & Event-driven	Spring Cloud Stream, RabbitMQ/Kafka integration		✅	✅	✅
Service Mesh Integration	Istio, Linkerd, Observability, Security			✅	✅
Spring Cloud Bus	Event broadcasting, Refresh events, Configuration updates		✅	✅	✅
Security	OAuth2, JWT, Spring Cloud Security, Single Sign-On		✅	✅	✅
Monitoring & Metrics	Micrometer, Prometheus, Grafana, Actuator integration		✅	✅	✅
Resilience Patterns	Retry, Rate Limiting, Bulkhead pattern		✅	✅	✅
Deployment & Cloud Platforms	AWS, Azure, Kubernetes, Docker integration	✅	✅	✅	✅
Advanced Topics	Reactive microservices, Function-as-a-Service, Serverless integration			✅	✅

Module / Topic	Annotations
Service Discovery	@EnableDiscoveryClient, @EnableEurekaClient, @EnableConsulClient, @EnableZookeeperClient
Load Balancing	@LoadBalanced, RibbonClient, @RibbonClient
Feign Clients	@EnableFeignClients, @FeignClient, @CircuitBreaker, fallback
Messaging / Stream	@EnableBinding, @StreamListener, @Input, @Output, @SendTo, @MessageMapping
Circuit Breaker / Resilience	@EnableCircuitBreaker, @CircuitBreaker, @Retryable, @Recover, @Bulkhead, @RateLimiter
Configuration / Property Management	@RefreshScope, @EnableConfigServer, @EnableConfigClient, @PropertySource
Scheduling / Async	@EnableScheduling, @Scheduled, @EnableAsync, @Async
Gateway / Routing	@EnableZuulProxy, @EnableGateway, @Route, @Predicates, @Filters
Security / OAuth	@EnableOAuth2Client, @EnableResourceServer, @EnableAuthorizationServer, @PreAuthorize, @RolesAllowed
API Gateway Filters	@GatewayFilter, @GlobalFilter, @PreFilter, @PostFilter
Cloud Stream Bindings	@Input, @Output, @EnableBinding, @StreamListener, @SendTo
Kubernetes / Cloud Native	@EnableKubernetes, @KubernetesDiscoveryClient, @RefreshScope
Spring Cloud Task	@EnableTask, @TaskExecution, @ScheduledTask
Spring Cloud Sleuth / Tracing	@EnableTracing, @NewSpan, @ContinueSpan, @SpanTag
Spring Cloud Vault	@EnableVaultConfiguration, @VaultPropertySource, @VaultPropertySourceProperty

Interview question

Basic Level

1. What is Spring Cloud and why do we use it?
2. Difference between Spring Boot and Spring Cloud.
3. What is a microservice in Spring Cloud context?
4. Explain service discovery in Spring Cloud.
5. What is Eureka Server?
6. What is Eureka Client?
7. How does client-side load balancing work in Spring Cloud?
8. What is Ribbon in Spring Cloud?
9. Difference between Ribbon and LoadBalancerClient.
10. What is Hystrix? Why is it used?
11. Explain the Circuit Breaker pattern.
12. What is Spring Cloud Config Server?
13. How does centralized configuration help in microservices?
14. What is Spring Cloud Bus?
15. Explain the difference between Spring Cloud Gateway and Zuul.
16. What is Feign Client in Spring Cloud?
17. How do you enable Feign in a Spring Cloud project?
18. What is a fallback method in Hystrix?
19. Explain service registration and discovery flow.
20. What is Spring Cloud Sleuth?
21. What is Zipkin? How does it integrate with Spring Cloud?
22. Difference between synchronous and asynchronous communication in microservices.
23. What are profiles in Spring Cloud Config?
24. How do you define routes in Spring Cloud Gateway?
25. What is distributed tracing in Spring Cloud?

---

Intermediate Level

1. How does Eureka handle service registration and deregistration?
2. What is self-preservation mode in Eureka?
3. Difference between Eureka, Zookeeper, and Consul.
4. How to secure Spring Cloud Config Server?
5. How to refresh properties dynamically in Spring Cloud Config?
6. What is Spring Cloud Stream?
7. What are binders in Spring Cloud Stream?
8. What is the role of Spring Cloud Bus with Kafka/RabbitMQ?
9. How does Spring Cloud Sleuth assign trace and span IDs?
10. Explain distributed logging in Spring Cloud.
11. What are retry mechanisms in Spring Cloud?
12. How to implement API Gateway authentication and authorization?
13. How does Spring Cloud Gateway handle rate limiting?
14. What is service-to-service communication in Spring Cloud?
15. How to use Feign Client for inter-service calls?
16. What is load balancing in Feign Client?
17. How to monitor microservices in Spring Cloud?
18. Explain Hystrix dashboard and Turbine.
19. How does Spring Cloud integrate with Kubernetes service discovery?
20. What are config labels and branches in Spring Cloud Config?
21. Explain Spring Cloud Contract for microservice testing.
22. What are refresh scopes in Spring Cloud?
23. How do you secure service-to-service communication?
24. What is the role of Zuul filters?
25. How does Spring Cloud Gateway support WebSockets?

---

Advanced Level

1. How does Spring Cloud handle scalability in microservices?
2. Explain the working of Resilience4j vs Hystrix.
3. How do you implement bulkhead patterns in Spring Cloud?
4. What is the difference between retry and circuit breaker?
5. How do you secure communication with OAuth2 in Spring Cloud?
6. How does Spring Cloud Config handle high availability?
7. What is Spring Cloud Consul and how is it used?
8. How do you implement blue-green deployment using Spring Cloud?
9. What is canary release strategy in Spring Cloud?
10. Explain distributed sessions with Spring Cloud.
11. How to implement event-driven architecture using Spring Cloud Stream?
12. What message brokers are supported by Spring Cloud Stream?
13. How to achieve fault tolerance in Spring Cloud microservices?
14. How to perform chaos testing in Spring Cloud applications?
15. What is Spring Cloud Data Flow?
16. Explain batch processing vs stream processing in Spring Cloud Data Flow.
17. How do you configure multiple environments in Config Server?
18. What is configuration encryption in Spring Cloud Config?
19. How do you integrate Spring Cloud with Vault?
20. How do you monitor circuit breakers at scale?
21. Explain reactive microservices with Spring Cloud.
22. How to achieve graceful degradation in Spring Cloud?
23. What are challenges in scaling Eureka Server?
24. How to design a resilient API Gateway?
25. How to handle failover in distributed microservices?

---

Expert Level

1. How do you design a large-scale system using Spring Cloud microservices?
2. Explain CAP theorem in the context of Spring Cloud services.
3. How does Spring Cloud achieve eventual consistency?
4. How to migrate from a monolith to Spring Cloud microservices?
5. How to implement multi-tenancy in Spring Cloud applications?
6. How to integrate Spring Cloud with Istio (service mesh)?
7. What is the Saga pattern? How do you implement it in Spring Cloud?
8. Explain choreography vs orchestration in distributed transactions.
9. How do you achieve zero-downtime deployment in Spring Cloud?
10. What is API composition pattern in microservices?
11. How to handle schema evolution in Spring Cloud microservices?
12. Explain distributed caching in Spring Cloud.
13. How do you integrate Spring Cloud with Kafka for event sourcing?
14. How do you ensure observability with Micrometer + Prometheus + Grafana?
15. How to build resilient CI/CD pipelines for Spring Cloud applications?
16. How does Spring Cloud handle network partitions?
17. How to design a fault-tolerant ecosystem with Spring Cloud?
18. What is polyglot persistence in microservices? How to manage it with Spring Cloud?
19. How do you implement advanced security (mTLS) in Spring Cloud?
20. How do you handle cross-cutting concerns (logging, tracing, metrics)?
21. What are best practices for managing secrets in Spring Cloud?
22. How do you perform chaos engineering in Spring Cloud?
23. Explain the role of Spring Cloud in hybrid cloud deployments.
24. How does Spring Cloud integrate with AWS/GCP/Azure?
25. How do you combine Spring Cloud with Domain-Driven Design (DDD)?

Related Topics

Config_Mgmt

Service Discovery

Load Balancing

API Gateway

Circuit Breaker

Service Mesh

Distributed Tracing