Core Java Essentials: Step-by-Step to Expert

🟢Java Basics

• Introduction to Java: Features, JVM, JRE, JDK

• Setting up environment (IDE, compiler)

• Data types, variables, operators

• Control statements: if-else, switch, loops

• Arrays and Strings

• Input/Output basics

🟡 Object-Oriented Programming (OOP)

• Classes and Objects

• Constructors and this keyword

• Inheritance (single, multilevel, hierarchical)

• Polymorphism (compile-time & runtime)

• Abstraction (abstract classes, interfaces)

• Encapsulation (access modifiers, getters/setters)

• Method overloading & overriding

🔵 Intermediate Topics

• Packages and Access Specifiers

• Exception Handling (try, catch, finally, throw, throws)

• Multithreading (Thread class, Runnable, synchronization)

• Collections Framework (List, Set, Map, Queue)

• Generics

• Inner Classes

• Java I/O (File handling, BufferedReader, Scanner)

🟣 Advanced Core Java

• JDBC (Java Database Connectivity)

• Networking (Sockets, URL, HTTP connections)

• Java Reflection API

• Lambda Expressions & Functional Interfaces

• Streams API (filter, map, reduce)

• Annotations

• Serialization & Deserialization

• Java Memory Management (Garbage Collection, Heap vs Stack)

• Concurrency utilities (ExecutorService, Future, CompletableFuture)

⚫ Enterprise & Modern Java

• Java 8+ Features (Optional, Streams, Date/Time API)

• Java 11+ Features (var keyword, HTTP Client API)

• Java 17+ Features (sealed classes, pattern matching)

• JUnit Testing & Mockito

• Design Patterns (Singleton, Factory, Observer, etc.)

• Best Practices (clean code, performance tuning)

📊 Quick Comparison Table