Java Tutorial

Java is a high-level, object-oriented programming language used to build web apps, mobile applications, and enterprise software systems.

• Known for its Write Once, Run Anywhere capability, which means code written in Java can run on any device that supports the Java Virtual Machine (JVM).
• Syntax and structure is similar to C-based languages like C++ and C#.

Try our ongoing free courses Java Skillup and Advance Java Skillup with weekly topic coverage, notes, daily quizzes and coding problems.

Why Learn Java?

• Used to build Android apps, desktop and web apps, enterprise backend systems, and cloud-based software.
• In high demand with many job opportunities in software development.
• Has popular frameworks like Spring and Hibernate which makes it powerful for enterprise applications.
• Supports object-oriented programming for clean, maintainable and reusable code.
• Top companies like Amazon, Netflix, and LinkedIn use Java.

Basics

Java basics form the foundation of your programming journey, covering essential concepts like syntax, data types, variables, loops, and conditionals.

• Introduction
• Download and Install Java
• JDK vs JRE vs JVM
• Identifiers
• Keywords
• Quiz: Java Basics and Identifiers
• Data Types
• Variables
• Operators
• Quiz: Variables, Operator
• Decision Making
• Loops & Jump Statements
• Quiz: Control Statements and Loops
• Project: Number Guessing Game

Methods

Java methods are reusable blocks of code that perform specific tasks and help organize your program. They improve code readability, reduce repetition, and make debugging easier.

• Introduction to Methods
• Static Methods vs Instance Methods
• Access Modifiers
• Command Line Arguments
• Variable Arguments (Varargs)
• Quiz: Methods

Arrays

Java arrays are containers that store multiple values of the same data type in a single variable. They provide an efficient way to manage and access collections of data using index-based positions.

• Introduction
• Declare and Initialize Arrays
• Multi-Dimensional Arrays
• Quiz: Java Arrays
• Jagged Arrays
• Arrays Class
• Final Arrays
• Quiz: Array
• Projects: Tic-Tac-Toe Game

Strings

Java Strings represent sequences of characters and are widely used in text processing. They are immutable, meaning once created, their values cannot be changed.

• Introduction
• Why Strings are Immutable
• String Concatenation
• String Methods
• Quiz: String Basics
• String Class
• StringBuffer Class
• StringBuilder Class
• Quiz: String Classes
• Strings vs StringBuffer vs StringBuilder

Regex

Java Regex (Regular Expressions) allows pattern matching and text manipulation using the java.util.regex package. It is powerful for validating, searching, and replacing strings based on specific patterns.

• What is Java Regex?
• Pattern Class
• Matcher Class
• Character Class
• Quantifiers
• Quiz: Regex Basics and Pattern Matching

OOP Concepts

Java follows the Object-Oriented Programming (OOP) paradigm, which organizes code into classes and objects. Core OOP principles like inheritance, encapsulation, polymorphism, and abstraction make Java modular and scalable.

• What are OOP Concepts?
• Classes and Objects
• Quiz: Classes and Objects
• Constructors
• Quiz: Constructors
• Object Class
• Abstraction
• Encapsulation
• Inheritance
• Quiz: Inheritance and Abstraction
• Polymorphism
• Packages
• Quiz: Polymorphism and Packages
• Project: Simple Banking Application

Interfaces

Java interfaces define a contract that classes must follow, specifying method signatures without implementations. They enable abstraction and support multiple inheritance in Java through a clean, structured approach.

• Interfaces
• Class vs Interface
• Quiz: Interfaces
• Functional Interface
• Nested Interface
• Marker Interface
• Quiz: Interface types and Comparator
• Project: Employee Management System

Exception Handling

Java Exception Handling is a mechanism to handle runtime errors, ensuring the program runs smoothly without crashing. It uses keywords like try, catch, throw, throws, and finally to manage exceptions.

• Exceptions
• Quiz: Java Exceptions
• Final, Finally and Finalize
• Throw and Throws
• Customized Exception Handling
• Chained Exceptions
• Null Pointer Exceptions
• Exception Handling with Method Overriding
• Quiz: Exception Handling

Memory Allocation

Java Memory Allocation refers to how memory is assigned to variables, objects, and classes during program execution. It involves stack and heap memory, with the JVM managing allocation and garbage collection automatically.

• Java Memory Management
• How Java Objects Stored in Memory?
• Quiz: Java Memory Allocation
• Types of Memory Areas Allocated by JVM
• Stack vs Heap Memory Allocation
• Quiz: Heap vs Stack
• Garbage Collection
• Quiz: JVM Memory Management and Garbage Collection
• Types of JVM Garbage Collectors
• Memory Leaks

Collections

Java Collections provide a framework for storing and manipulating groups of objects efficiently. It includes interfaces like List, Set, and Map, along with classes like ArrayList, HashSet, and HashMap.

• Collections Class
• Collection Interface
• Quiz: Collection
• List Interface
• ArrayList
• LinkedList
• Quiz: List, ArrayList, LinkedList
• Set Interface
• HashSet
• TreeSet
• Quiz: Set and HashSet
• Queue Interface
• Priority Queue
• Deque Interface
• Map Interface
• HashMap
• Quiz: Queue and Map Interface
• Iterator
• Comparator Interface
• Comparable Interface
• Quiz: Iterators, Comparator vs Comparable
• Project: Face Detection System

Lambda Expressions and Streams

Java Streams and Lambda Expressions simplify data processing by enabling functional-style operations on collections. Lambdas provide concise syntax for anonymous functions, while Streams allow efficient filtering, mapping, and reduction of data.

• Lambda Expressions
• Method References
• Java Streams
• Quiz: Lambda Expressions and Streams
• To know Java 8 in detail, refer to - Java 8 Features

Multithreading and Synchronization

Java Multithreading allows concurrent execution of two or more threads, enabling efficient CPU utilization and faster program performance. It is commonly used for tasks that required parallel processing and responsiveness from multiple ends.

• Introduction
• Threads
• Thread.start() vs Thread.run() Method
• Thread.sleep() Method
• Runnable Interface
• Quiz: Thread Basics and Lifecycle
• Main Thread
• Thread Priority in Multithreading
• Daemon Thread
• Quiz: Thread Methods and Daemon Threads
• Java Synchronization
• Quiz: Synchronization Basics
• Thread Safety
• Locks in Java
• Lock vs Monitor in Concurrency
• Lock Framework vs Thread Synchronization
• Reentrant Lock
• Deadlock in Multithreading
• Thread Pools
• Executor Framework
• Quiz: Deadlocks and Synchronization
• Project: Snake Game

File Handling

Java File Handling enables programs to create, read, write, and manipulate files stored on the system. It uses classes from the java.io and java.nio packages for efficient file operations.

• Introduction to Java IO
• Reader Class
• Writer Class
• File Handling
• File Class
• Quiz: File Handling
• FileInputStream
• FileOutputStream
• FileReader Class
• FileWriter Class
• FileOutput Stream
• BufferedReader Input Stream
• BufferedReader Output stream
• Fast I/O
• Quiz: File Writing
• FilePermission Class
• FileDescriptor Class
• Project: Text Editor

Networking

Java Networking enables communication between devices over a network using classes from the java.net package. It supports protocols like TCP and UDP for building client-server applications and data exchange.

• Introduction to Java Networking
• Quiz: Networking Basics and Protocols
• Socket Programming
• Server Socket Class
• Quiz: Sockets and Server Communication
• URL Class and Methods
• Project: Chat Application

Java Database Connectivity(JDBC)

• Introduction to Java JDBC
• JDBC Driver
• JDBC Connection
• Types of Statements in JDBC
• Quiz: JDBC

Interview Questions

Prepare for Java interviews with these commonly asked questions, covering core concepts, OOP, collections, multithreading, exception handling, and frameworks like Spring and Hibernate.

• Core Java Interview Questions and Answers

Important Links

• Comparison of various programming languages
• Companies That Use Java
• Careers & Jobs in Java

Practice

• Java Exercises – Basic to Advanced Java Practice Programs
• Java Coding Practice Problems
• Java Language MCQs with Answers

Introduction to Java

Visit Course

Introduction to Java

Writing First Program in Java

Variables and Primitive DataTypes

Non Primitive DataTypes

Type Conversion in Java

Input in Java