☕ Java Knowledge Hub

Enterprise Java Notes • Interview Questions • Code Examples • Cheat Sheets

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Core Java

OOPs Concepts

Encapsulation, Inheritance, Polymorphism, Abstraction, SOLID Principles and Interview Questions.

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Collections Framework

List, Set, Map, Queue, Internal Working, Interview Questions and Examples.

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Stream API

Filter, Map, FlatMap, Reduce, Collectors, Grouping, Sorting and Examples.

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Multithreading

Threads, Synchronization, Executor Framework, Callable, Future and Locks.

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Exception Handling

Checked Exceptions, Runtime Exceptions, Custom Exceptions and Best Practices.

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JDBC

Connection, Statement, PreparedStatement, Transactions and Batch Processing.

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Spring Ecosystem

Spring Core

IOC, Dependency Injection, Bean Lifecycle and Configuration.

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Spring Boot

Auto Configuration, REST APIs, Validation, JPA, Security and Enterprise Development.

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Microservices

API Gateway, Eureka, Config Server, Feign Client, Resilience4j and Distributed Systems.

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Advanced Topics

Design Patterns

Singleton, Factory, Builder, Strategy, Observer and Enterprise Patterns.

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Coming Soon...

More Java concepts, tutorials and enterprise examples will be added regularly.

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Interview Preparation

Java Interview Questions

Frequently Asked Core Java Interview Questions with Answers and Examples.

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Coding Interview Questions

Programming Problems, Patterns and Coding Round Interview Preparation.

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Spring Boot Interview Questions

Spring Boot, REST APIs, Security and JPA Interview Questions with Answers.

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Microservices Interview Questions

API Gateway, Eureka, Config Server, Resilience4j and Distributed Systems Interview Questions.

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Cheatsheets

01. Core Java

OOPs, Data Types, Operators, Loops, Arrays, Strings, and Fundamentals.

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02. Collections Framework

List, Set, Map, Queue, Internal Working, and Interview Questions.

Open

03. Multithreading & Exception Handling

Threads, Synchronization, Executor Framework, Locks, Callable & Future.

Open

04. Java 8 Features

Lambda, Stream API, Functional Interfaces, Optional, Date & Time API.

Soon

05. JVM & Memory Management

JVM Architecture, Heap, Stack, Garbage Collection, Class Loader.

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06. Spring Core

IOC, Dependency Injection, Bean Lifecycle, Configuration, AOP.

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07. Spring Boot

Auto Configuration, REST APIs, Validation, Profiles, Actuator.

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08. Spring MVC & REST API

Controllers, Request Mapping, DTOs, Validation, REST Best Practices.

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09. Spring Data JPA & Hibernate

Entity Mapping, Repositories, JPQL, Relationships, Performance.

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10. Spring Security + JWT

Authentication, Authorization, JWT, Filters, Role-Based Security.

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11. Microservices

Service Discovery, API Gateway, Config Server, Feign, Resilience4j.

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Excel Interview Prep Hub

All Questions & Answers

Browse, filter, and practice interview questions synced from an Excel workbook, covering 0-10 YoE topics.

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