Java Tutorial
Last Updated :
24 Mar, 2025
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Java is one of the most popular and widely used programming languages.
- Used to develop mobile apps, desktop apps, web apps, web servers, games, and enterprise-level systems.
- Java was invented by James Gosling and Oracle currently owns it. JDK 23 is the latest version of Java.
- Java's syntax is similar to C/C++.
- Popular platforms like LinkedIn, Amazon, and Netflix rely on Java for their back-end architecture, showcasing its stability and scalability across different environments.
- Popularity is so high that 3 Billion+ devices use Java across the world.
Java Hello World Program
// A Java program to print "Hello World"
public class GFG {
public static void main(String args[])
{
System.out.println("Hello World");
}
}
// Output:"Hello World"
Java Basics
- What is Java?
- Download and Install Java?
- JDK vs JRE vs JVM
- Identifiers
- Keywords
- Data Types
- Quiz: Java Data Types
- Variables
- Operators
- Decision Making (if, if-else, switch, break, continue, jump)
- Loops
Java Methods
- Introduction to Methods
- How to Call Methods?
- Static Methods vs Instance Methods
- Access Modifiers
- Command Line Arguments
- Variable Arguments (Varargs)
Java Arrays
- Introduction to Arrays
- Declare and Initialize Arrays
- Multi-Dimensional Arrays
- Jagged Arrays
- Arrays Class
- Final Arrays
- Java Array Programs
- Quiz: Java Arrays
Java Strings
- Introduction of Strings
- Why Strings are Immutable?
- Java String Concatenation
- String Class
- StringBuffer Class
- StringBuilder Class
- Strings vs StringBuffer vs StringBuilder
- Java String Programs
Java OOPs Concepts
- What are OOPs Concepts?
- Classes and Objects
- Quiz: Classes and Objects
- Constructors
- Quiz: Constructors
- Object Class
- Abstraction
- Encapsulation
- Inheritance
- Polymorphism
- Packages
- Quiz: Packages
Java Interfaces
- Java Interfaces
- Interfaces and Inheritance
- Class vs Interface
- Functional Interface
- Nested Interface
- Marker Interface
- Comparator Interface
- Quiz: Interface and Abstract Class
Java Collections
- Java Collection Framework
- Collections Class
- Collection Interface
- List Interface
- Set Interface
- Queue Interface
- Map Interface
- SortedSet Interface
- Comparator Interface
- Comparable Interface
- Comparator vs Comparable
- Iterator
Java Exception Handling
- Java Exceptions
- Checked vs Unchecked Exceptions
- Try Catch Block
- Final, Finally and Finalize
- Throw and Throws
- Customized Exception Handling
- Chained Exceptions
- Null Pointer Exceptions
- Exception Handling with Method Overriding
- Quiz: Exception Handling
Java Multithreading
- Introduction to Java Multithreading
- Threads
- Thread Class
- Runnable Interface
- Lifecycle and States of a Thread
- Main Thread
- Thread Priority in Multithreading
- Naming & Feteching Name of Current Thread
- Thread.start() vs Thread.run() Method
- Thread.sleep() Method
- Daemon Thread
- Thread Safety
- Thread Pools
Java File Handling
- File Handling
- File Class
- Create Files
- Read Files
- Write on Files
- Delete File
- FileReader Class
- FileWriter Class
- FilePermission Class
- FileDescriptor Class
Java Streams and Lambda Expressions
- Lambda Expressions
- Method References
- Java Stream - Complete Tutorial
- Java 8 Features - Complete Tutorial
Java IO
- Introduction to Java IO
- Reader Class
- Writer Class
- FileInput Stream
- FileOutput Stream
- BufferedReader Input Stream
- BufferedReader Output stream
- BufferedReader vs Scanner
- Fast I/O
Java Synchronization
- Java Synchronization
- Importance of Thread Synchronization
- Method and Block Synchronization
- Atomic vs Volatile vs Synchronized
- Local Frameworks vs Thread Synchronization
- Deadlock in Multithreading
- Deadlock Prevention and Avoidance
- Lock vs Monitor in Concurrency
- Reentrant Lock
Java Regex
Java Networking
- Introduction to Java Networking
- TCP Architecture
- UDP Architecture
- IPV4 vs IPV6
- Connection-Oriented vs Connectionless Protocols
- Socket Programming
- Server Socket Class
- URL Class and Methods
Java Database Connectivity(JDBC)
Java Memory Allocation
- Java Memory Management
- How Java Objects Stored in Memory?
- Stack vs Heap Memory Allocation
- Java Virtual Machine(JVM) Stack Area
- Types of Memory Areas Allocated by JVM
- Garbage Collection
- Types of JVM Garbage Collectors
- Heap and Stack Memory Allocation
- Memory Leaks
Java Interview Questions
Java Program Examples
Java Coding Practice Problems
- Java Fundamentals Coding Practice Problems
- Java Methods Coding Practice Problems
- Java Arrays Coding Practice Problems
- Java Strings Coding Practice Problems
- Java OOPs Coding Practice Problems
- Java Sorting and Searching Algorithms Coding Practice Problems
- Java Collections Coding Practice Problems
- Java Stream & Lambda Expression Coding Practice Problems
Java Quizzes and MCQs
Java Projects
- Number Guessing Game
- Simple Banking Application
- Currency Converter
- Tic-Tac-Toe Game
- Snake Game
- Memory Game
- Chat Application
- Face Detection System
- Social Networking Site
- Text Editor
Java Jobs & Opportunities
According to report of Statista, Java is most demanded programming languages after JavaScript by recruiters worldwide in 2024. Major MNC companies are recruiting Java Programmers.
- Amazon
- IBM
- Honeywell
- Netflix
- Meta
- Wipro
- Infosys
- Accenture
- Oracle Inc
- Deloitte India
- Cognizant
- Capgemini and Many more...
FAQs - Learn Java Programming
What is Java?
Developed by Sun Microsystems in 1995, Java is a highly popular, object-oriented programming language. This platform independent programming language is utilized for Android development, web development, artificial intelligence, cloud applications, and much more.
Why use Java ?
Java is simple to understand programming language because doesn’t contain concepts like : Pointers and operator overloading and it is secure and portable.
What are the major concepts in Java?
There are 4 major concept in Java that is abstraction, encapsulation, polymorphism, and inheritance. Along with this Java also works with three OOPs concept
How Java different to C++ ?
| C++ | JAVA |
|---|---|
| C++ is platform dependent. | Java is platform independent. |
| C++ uses compiler only. | Java uses compiler and interpreter both. |
| C++ support pointers and operator overloading. | Java doesn’t support pointers and operator overloading concept. |
Why Java is so popular programming language?
Java is based on object model hence it is one the popular programming language.
What are the scope of Java Technologies for Web Applications?
Java Technologies for Web Applications are a set of Java-based technologies that are used to develop web applications. These technologies include:
- Java Servlet API
- JavaServer Pages
- JavaServer Faces
- Enterprise JavaBeans
- JDBC (Java Database Connectivity)
- Java Messaging Service (JMS)
- JavaMail API
- JAX-WS
