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Java Tutorial

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Java Introduction What is Java?History & Features JDK vs JRE vs JVM How Java Works Install Java & Setup First Java Program Java vs Other Languages

Syntax & Structure Java Keywords & Reserved Words Naming Conventions Data Types Variables Type Casting Operators Increment & Decrement Operators Escape Sequences Math Class User Input (Scanner)Command Line Arguments Wrapper Classes Autoboxing & Unboxing final Keyword Comments

if Statement if-else Statement else-if Ladder Nested if switch Statement for Loop while Loop do-while Loop for-each Loop Nested Loops break Statement continue Statement return Statement

Methods Overview Parameters & Return Types Method Overloading Recursion Variable Arguments (varargs)Pass by Value vs Pass by Reference

Arrays Basics Multi-dimensional Arrays Array Methods (Arrays class)Passing Arrays to Methods

String Basics String Methods String Comparison equals() vs ==String Pool StringBuilder StringBuffer String vs StringBuilder vs StringBuffer Immutable Strings String Formatting String Class Deep Dive

Packages in Java Creating Custom Packages import Statement Access Modifiers Deep Dive public Modifier private Modifier protected Modifier default (package-private)

Inner Classes Static Nested Class Anonymous Classes Enums Records (Java 16+)Sealed Classes (Java 17+)Immutable Classes Object Cloning Shallow vs Deep Copy Serialization & Deserialization Annotations Built-in Annotations Custom Annotations Reflection API Practice Questions

What is Exception Handling?Exception vs Error Exception Hierarchy Checked vs Unchecked Exceptions Common Java Exceptions try-catch Multi-catch finally Block try-with-resources throw Keyword throws Keyword throw vs throws Custom Exceptions Exception Propagation

Generics Basics Generic Methods Generic Classes Bounded Type Parameters Wildcards Type Erasure

Introduction to Date & Time API LocalDate LocalTime LocalDateTime ZonedDateTime Period Duration DateTimeFormatter Legacy Date vs New API

Java 8 Key Features Java 11 Features Java 17 Features (LTS)Java 21 Features (LTS)var (Local Type Inference)Text Blocks Pattern Matching Switch Expressions Virtual Threads (Java 21)

File & Path Basics Reading Files Writing Files BufferedReader & Writer NIO.2 (java.nio)Serialization Externalization Serialization vs Externalization

Introduction to JDBC JDBC Architecture DriverManager Connection Statement PreparedStatement CallableStatement ResultSet CRUD Operations Transaction Management Connection Pooling

Threads Basics Runnable & Callable Thread Lifecycle Synchronization volatile Keyword Race Conditions Deadlock Livelock Starvation wait, notify & notifyAll Lock & ReentrantLock Semaphore Atomic Variables ConcurrentHashMap Executor Framework CompletableFuture ForkJoinPool Practice Questions

JVM Architecture Stack Memory Heap Memory Stack vs Heap Memory Garbage Collection Metaspace vs PermGen ClassLoader JIT Compiler

Design Patterns Overview Singleton Pattern Factory Pattern Abstract Factory Pattern Builder Pattern Prototype Pattern Adapter Pattern Decorator Pattern Facade Pattern Proxy Pattern Observer Pattern Strategy Pattern Template Method Pattern Command Pattern

Student Management System Library Management System Employee Management System Bank Management System

Array Problems String Problems HashMap Problems Stream Problems Multithreading Problems

Top Java Interview Q&A Core Java Interview Questions OOP Interview Questions String Interview Questions Array Interview Questions Collections Interview Q&A Multithreading Q&A Exception Handling Q&A Java 8+ Interview Q&A FAANG Java Questions Coding Challenges

Clean Code in Java SOLID Principles DRY, KISS & YAGNI Effective Java Tips Common Anti-Patterns Code Review Checklist

Beginner Mistakes OOP Mistakes Collections Mistakes Streams Mistakes Exception Handling Mistakes Concurrency Mistakes Performance Pitfalls Memory Leaks

Spring Boot Introduction Dependency Injection (DI)Spring Annotations REST API with Spring Boot Spring Data JPA Exception Handling in Spring Spring Boot Testing Spring Boot Interview Q&A

Java Tutorial

What is Java?

Java is a high-level, class-based, object-oriented programming language designed to have as few implementation dependencies as possible. It follows the "Write Once, Run Anywhere" principle — compiled Java code runs on any platform that supports the JVM without recompilation.

Our tutorial covers everything from basics to modern Java — including OOP, Collections, Streams, Multithreading, Generics, Design Patterns, Modern Java 8–21, and more.

Beginners Guide

Practice Problems

Learning Roadmap

Java Fundamentals

Java Basics

Master the foundational building blocks of Java — variables, data types, operators, control flow, and methods. A strong grasp of these basics is essential before moving to object-oriented concepts.

Control Flow

Methods

Arrays

Strings

›String Basics
›String Methods
›String Comparison
›equals() vs ==
›String Pool
›StringBuilder
›StringBuffer
›String vs StringBuilder vs StringBuffer
›Immutable Strings
›String Formatting
›String Class Deep Dive

Object-Oriented Programming

Java is built around OOP. Learn classes, objects, inheritance, polymorphism, encapsulation, and abstraction — the four pillars that make Java code modular, reusable, and maintainable.

Packages & Access Control

Advanced OOP

Exception Handling

Collections Framework

The Java Collections Framework provides ready-made data structures — List, Set, Map, Queue, and more. Understanding when and how to use each collection is a core Java skill.

Generics

Generics allow you to write type-safe, reusable code. Learn how to parameterize classes and methods, understand wildcards, and avoid ClassCastExceptions at runtime.

Functional Programming in Java

Date & Time API

Modern Java (8–21)

File I/O

JDBC

Multithreading

JVM & Memory

Design Patterns

Design patterns are proven solutions to recurring software design problems. Learn the most important creational, structural, and behavioral patterns and when to apply them in Java.

Mini Projects

Coding Problems

Interview Preparation

Targeted preparation for Java technical interviews — top questions from FAANG and product-based companies, common coding patterns, and system design fundamentals for Java engineers.

Best Practices

Common Mistakes & Pitfalls

Spring Boot