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Java Roadmap 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)Wrapper Classes Autoboxing & Unboxing final Keyword Comments

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

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

String Basics String Methods String Comparison equals() vs ==String Pool Immutable Strings StringBuilder String Formatting Practice Questions

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

Classes & Objects Constructors this Keyword static Keyword Encapsulation Inheritance super Keyword Polymorphism Method Overriding Method Overloading vs Overriding Abstraction Abstract Classes Interfaces Abstract Class vs Interface Object Class & toString()

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

Inner Classes Anonymous Classes Enums Records (Java 16+)Sealed Classes (Java 17+)Annotations Built-in Annotations Custom Annotations Reflection API Design Patterns Overview

Collections Overview ArrayList LinkedList Stack Queue HashSet & LinkedHashSet TreeSet HashMap & LinkedHashMap TreeMap PriorityQueue Deque & ArrayDeque Iterator ListIterator Comparable Comparator Comparable vs Comparator Collections Utility Class Choosing the Right Collection Practice Questions

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

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)

Exception Hierarchy try-catch finally Block try-with-resources throw Keyword throws Keyword Difference Between throw and throws Checked vs Unchecked Custom Exceptions Multi-catch Exception Propagation Practice Questions

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

Threads Basics Runnable & Callable Thread Lifecycle Synchronization volatile Keyword Race Conditions Deadlock wait, notify & notifyAll Executor Framework CompletableFuture Practice Questions

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

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 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

Heap Memory

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PreviousStack Memory

NextStack vs Heap Memory

heap memory | Java Tutorial | DevStackFlow