About this Tutorial

This tutorial is designed for programmers from beginner to advanced levels.

We have tried to explain the core concepts, provide simple programs to demonstrate them, and summarize the things to remember in a concise way.

Beginners can clarify their understanding by going through the concepts and practicing the simple programs. Experienced programmers can quickly go through the simple programs and things to remember, and apply them in their own projects.

What is Java:

Java is one of the most popular programming languages in the world introduced in 1995, It was introduced by Sun Microsystems. Currently, Java is owned by Oracle. Java can run in any platform like Windows, macOS, or Linux that has a Java Virtual Machine (JVM), which makes it highly portable and versatile. It is widely used in various domains, including web applications, mobile applications, enterprise applications, and more. It is very easy to learn and has a large community of developers, which makes finding resources and support easier.

What is a Programming Language?

Programming language is a set of instruction and commands used to communicate with machines. It translates human-readable code into machine code (binary) so that computers can perform specific tasks.

It is widely used for building enterprise applications, Android apps, and backend systems.

The main key features of Java:

Simple - Java provides structured and readable syntax, making it easier or beginner-friendly for new developers to write and understand code.

Platform Independent (Write Once, Run Anywhere) - Java code can be easily transferred and run across different operating systems like Windows, macOS, and Linux without rewriting the code.

Object-Oriented Programming (OOP) - It organizes code into reusable parts called objects, making it easier to scale and maintain.

Robust and Secure - Java uses automatic garbage collection which reduces memory leaks and crashes. Java code runs inside the JVM which restricts unauthorized access to memory.

Multithreaded - It has built-in capabilities for multithreading, that is it can create, run and manage multiple threads. Which helps to perform or execute multiple tasks simultaneously.

Community Support - It has huge community support which makes it easier for developers to find help, share knowledge, and collaborate on projects.

Open-source and Free - Java is available through OpenJDK, a free and open-source implementation that you can use to develop and run Java programs.

Sample Java Program

Example:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Result:

Hello, World!

What will we learn next

We will learn the following Java topics step by step.

• Java Fundamentals: JVM, JRE, JDK, Java installation, compilation and execution, your first Java program, and comments.
• Java Variables
• Java Data Types
• Java Type Casting
• Java Operators
• Java Input/Output
• Control Statements: if and if-else, do-while and for loops, break, and continue.
• Java Classes and Objects
• Java Methods
• Java Constructors
• Java this Keyword
• OOP Principles: encapsulation, inheritance, polymorphism, and abstraction.
• Java super Keyword
• Java Method Overloading and Overriding
• Java Modifiers: access modifiers and non-access modifiers.
• Java Interfaces
• Java Abstract Classes
• Association, Aggregation, and Composition
• Java Arrays: single-dimensional arrays, multidimensional arrays, and array methods.
• Java Strings: the String class, StringBuffer, string methods, immutable and mutable strings, ways to create strings, and the string pool.
• Collections Framework: List (ArrayList, LinkedList, Vector, Stack), Set (HashSet, LinkedHashSet, TreeSet), Queue (Queue interface, PriorityQueue, Deque), Map (HashMap, LinkedHashMap, TreeMap, Hashtable), Iterator, Comparable, and Comparator.
• Multithreading: Thread class, Runnable interface, thread lifecycle, synchronization, inter-thread communication, deadlock, and the Executor framework.
• File Handling: working with files, serialization, and deserialization.
• Advanced Java: reflection, annotations, generics, inner classes, anonymous classes, enums, wrapper classes, autoboxing, and unboxing.
• Java Memory Management
• Design Patterns
• JDBC (Database Connectivity)
• Java IDEs
• Interview Preparation: questions for freshers and developers with three or five years of experience.