kumarh1982/interview-notes

All are realtime interview questions and answers. I am adding more on daily basis whenever I am getting time.

Interview Notes

Interview questions and answers

• Object-oriented programming(OOPS)

  • OOPS
    • Abstraction
    • Encapsulation
    • Polymorphism
    • Abstract Class
    • Does Abstract class have constructor?
    • Abstract class Vs Interface
    • What to choose – interface or abstract class
    • Why Java 8 has introduced default methods?
    • Why Java 8 has introduced static methods?
    • Why Java does not allow multiple inheritance?
    • Method Overloading and Overriding
      • Method Overloading
      • Rules for Method Overloading
      • Method Overriding
      • Rules for Method Overriding
      • Test

• Java

  • Basic

    • Java 8
      • Java 8 Features
      • New features
      • Lambda Expressions
      • Why use Lambda Expression
      • Lambda Expressions Syntax
      • Lambda Expressions Syntax
      • Lambda Expressions Examples
      • Functional Interface
      • Test
      • Test
      • Test
    • Why String is Immutable?
    • StringBuffer and StringBuilder
    • equals and hashcode contract
    • Comparable and Comparator interfaces
    • static keyword
    • Shallow Copy and Deep Copy
    • Serialization and De-serialization
    • Serialization scenarios with Inheritance
    • How to make a class Immutable?
    • Class loaders in Java
    • Garbage Collector
      • How does the garbage collector work?
      • Types of garbage collectors
      • Garbage Collection and types of Garbage Collectors
      • final, finally and finalize()
    • String, StringBuffer, StringBuilder
    • Reflection
    • Exceptions
      • Checked and Unchecked Exception
      • Custom exception
      • OutOfMemoryError
    • Generics in Java

  • Collection Framework

    • HashMap
    • Interal working of put() and get() methods of HashMap
    • HashMap collisions
    • equals and hashCode method in HashMap when the key is a custom class
    • Concurrent HashMap
    • HashSet class
    • TreeMap
    • TreeSet
    • fail-safe and fail-fast iterators
    • Lists
      • LinkedList
      • Stack
      • Vector
      • CopyOnWriteArrayList
      • Collections.synchronizedList
    • Sets
      • HashSet
      • LinkedHashSet
      • TreeSet
      • ConcurrentSkipListSet
      • CopyOnWriteArraySet
      • EnumSet
    • Maps
      • HashMap
      • HashMap implementation details
      • LinkedHashMap
      • Hashtable
      • ConcurrentHashMap
      • TreeMap
      • ConcurrentSkipListMap
    • Queues
      • LinkedList
      • ArrayBlockingQueue
      • LinkedBlockingQueue
      • ConcurrentLinkedQueue
      • Deque classes
      • PriorityQueue
      • PriorityBlockingQueue
      • DelayQueue
      • SynchronousQueue
    • equals and hashCode
    • Hierarchy and classes

  • Multi threading

    • Life Cycle of a Thread
    • Creating a Thread
    • Life Cycle of a Thread
    • Creating a Thread
    • What does join() method?
    • Deadlock
    • How to avoid deadlock?
    • What will happen if I directly call the run() method and not the start() method to execute a thread?
    • Once a thread has been started can it be started again?
    • Why wait, notify and notifyAll methods are defined in the Object class instead of Thread class?
    • Why wait(), notify(), notifyAll() methods must be called from synchronized block?
    • wait() vs sleep() methods
    • Executor Framework
    • Test

• Spring

  • Spring
    • Dependency Injection
      • Types of Dependency Injection
      • Constructor-based DI
      • Setter-method injection
      • Constructor Vs Setter injection
    • BeanFactory and ApplicationContext
    • Spring Bean life-cycle
    • Spring Bean Scopes
    • What happens when we inject a prototype scope bean in a singleton scope bean?
    • How to inject a prototype scope bean in a singleton scope bean?
    • Stereotype Annotations
    • @Controller vs @RestController annotation
    • @Qualifier annotation
    • @Transactional annotation
    • @ControllerAdvice annotation
    • @Bean annotation
    • @Component vs @Bean annotation
    • Spring Boot Security using OAuth2 with JWT
    • OAuth2 Terminology
    • Json Web Token(JWT)
    • Spring Boot Rest Authentication with JWT Token Flow
    • Spring Transaction Management
      • Global Transactions
      • Local Transactions
      • Programmatic Approach:
      • Declarative Approach (@Transactional)
      • propagation
      • isolation
      • readOnly
      • timeout

• HTTP Verbs

  • HTTP Verbs
    • GET
    • POST
    • PUT
    • DELETE
    • PATCH
    • OPTIONS
    • HEAD

• HTTP Status Codes

  • HTTP Status Codes

    • 1×× Informational

    • 2×× Success

      • 200 OK
      • 201 Created
      • 202 Accepted
      • 204 No Content
      • 205 Reset Content

    • 3×× Redirection

      • 300 Multiple Choices

    • 4×× Client Error

    • 5×× Server Errorl

• Hibernate

  • Hibernate
    • JPA vs Hibernate
    • @Entity annotation
    • @Id & @GeneratedValue
    • get() and load() methods of Hibernate Session
    • Session and SessionFactory
    • First Level and Second Level Cache
    • Test

• Angular interview questions and answers

  • Angular
    • AngularJS vs Angular
      • AngularJS
      • Angular
      • Why Angular
        • Components
        • Templates
        • Dependency injection
        • Angular Routing and Navigation
    • Angular Module
    • Bootstrapping Module
    • JIT vs AOT compilation
    • Advantages of AOT
    • What are the ways to control AOT compilation?
    • How to optimize loading large data in angular?
    • How an Angular application gets started or loaded?
    • Angular Services
    • What is Interpolation
    • Angular Routing and Navigation
    • Angular Component
      • What Is an Angular Component?
        • Template
        • Class
        • Component Metadata
      • Communication Between Components
        • Parent to Child
        • Child to Parent
        • Child to Parent
        • Unrelated Components
    • Angular Directive
      • Components Directives
      • Structural Directives
      • Attribute Directives
      • How to Create Custom Directives?
      • Structural Directive vs Attribute Directive
      • Component vs Directive
    • Angular Pipes
      • Syntax to use Pipes in Angular Application
      • Types of Pipes in Angular
        • 1. Built-in Pipes
        • 2.Custom Pipes
      • Parameterized Pipe
      • Custom Pipe
      • Pure vs Impure Pipe
    • Angular Data Binding
      • 1. Interpolation
      • 2. Property binding
      • 3. Event binding
      • 4. Two-way data binding
    • Angular Lazy Loading
    • Angular Lifecycle Hooks
      • ngOnChanges
      • ngOnInit
      • ngDoCheck
      • ngAfterContentInit
      • ngAfterContentChecked
      • ngAfterViewInit
      • ngAfterViewChecked
      • ngOnDestroy
      • constructor() vs ngOnInit()
    • RxJS
      • Utility functions provided by RxJS
      • RxJS Operator
      • What is subscribing
      • Observable
      • Observer
      • Error handling in observables
      • Observable creation functions
      • What will happen if you do not supply handler for observer?
      • Promise vs Observable
      • Async Pipe
      • HttpClient
        • Error handling

• Design Patterns interview questions and answers

  • Design Patterns
    • Creational Design Patterns
      • Simple Factory
      • Factory Method
      • Abstract Factory
      • Builder
      • Prototype
      • Singleton
    • Structural Design Patterns
      • Adapter
      • Bridge
      • Composite
      • Decorator
      • Facade
      • Flyweight
      • Proxy
    • Behavioral Design Patterns
      • Chain of Responsibility
      • Command
      • Iterator
      • Mediator
      • Memento
      • Observer
      • Visitor
      • Strategy
      • State
      • Template Method

• Microservices

  • Microservices
    • Advantages of Microservices Architecture
    • Disadvantages of Microservices
    • Challenges of Microservices Architecture
    • Gateway
    • Microservices Monitor
    • Microservices vs Monolithic Architecture
    • How does Microservice Architecture work?
    • Communicating Between Microservices
    • SOAP vs REST
    • Eureka Naming Server
    • Zuul
    • Zipkin
    • Hysterix

• Kafka

  • Kafka
    • Advantages of Kafka
    • Offset in Kafka
    • Consumer group in Kafka
    • ZooKeeper in Kafka
    • Can I use Kafka without Zookeeper?
    • What is Zookeeper in Kafka? Can we use Kafka without Zookeeper?
    • Partition in Kafka
    • APIs of Kafka
    • Load balancing of the server in Kafka
    • Retention period in Kafka cluster
    • RabbitMQ vs Apache Kafka
    • Explain Apache Kafka Use Cases?
    • Kafka Cluster, and its key benefits
    • Replicas in Kafka
    • Starting a Kafka server
    • In the Producer, when does QueueFullException occur?
    • Confluent Kafka vs. Apache Kafka

• MongoDB

  • MongoDB
    • Key Components
    • Document
    • Collection
    • Namespace
    • Databases in MongoDB
    • Mongo Shell
    • Advantages of MongoDB:
    • Features of MongoDB
    • Indexes in MongoDB
    • MongoDB

• Database Database

  • SQL
    • Joins
      • Inner join
      • Left outer join
      • Right outer join
      • Full join
      • Cross join
      • Self Join
    • Keys
    • Indexes
    • Queries
  • Frequently asked queries
    • Find all departments with sales more than 1000
    • Print all employee ids with their manager ids
    • Print all manager names with count of directs
    • Print 10th highest salary

• Maven

  • Maven

• Unix

  • Unix
    • Find
    • Search
    • Processes
    • File permissions
    • List files
    • Symlinks
    • Checking logs
    • Text manipulation
    • Sed
    • Networking
    • Space
    • Miscellaneous

• DevOps Tools

  • Docker
  • Git
    • Advantages of git
    • git push
    • git pull vs git fetch
    • conflict
    • resolve a conflict
    • git clone
    • git pull origin
    • git commit a
  • Jenkins
  • Kubernetes