Core Java

Java Fundamentals

• Data types, variables, operators

• Control flow (if, switch, loops)

• Arrays and Strings

Object-Oriented Programming (OOP)

• Classes and Objects

• Inheritance, Polymorphism, Encapsulation, Abstraction

• Interfaces and Abstract classes

Exception Handling

• Try-catch blocks, throws, finally

• Custom exceptions

Collections Framework

• List, Set, Map, Queue

• ArrayList, LinkedList, HashSet, TreeSet, HashMap, TreeMap, etc.

Multithreading & Concurrency

• Threads, Runnable, ExecutorService

• Synchronization, wait-notify

File I/O and Serialization

• File handling using java.io and java.nio

• Serializable interface

Java 8+ Features

• Lambda expressions

• Streams API

• Functional interfaces

• Method references and Optional

JVM Internals (basic knowledge)

• Memory management (Heap, Stack, GC)

• Class loading

• Performance tuning basics