Introduction to Java

History of Java

Java is a programming language that James Gosling and his team at Sun Microsystems created in the middle of the 1990s. It was initially developed for consumer electronics but later gained popularity for web applications and business software.

Java's "write once, run anywhere" guiding principle made it portable and platform-adaptable. Oracle now owns it, and many applications are developed using it.

Versions of Java

New versions of Java are consistently being released as it continues to develop. Every new version typically keeps backward compatibility with previous versions while adding new features and improvements.

Since its initial release in 1996, Java has undergone several revisions, adding new functions and improvements. Java 1.0, Java 2, Java 5, Java 8, Java 11 (LTS), and Java 12–18 are notable versions.

Java 1.0

Platform independence, automatic memory management, and rubbish collection were just a few of the crucial features that Java 1.0 introduced.

Java 2

The Swing GUI toolkit, Java Naming and Directory Interface (JNDI), and Java Database Connectivity (JDBC) API are just a few of the new features that came with Java 2.

Java 5

With Java 5, new language features like generics, annotations, and autoboxing were available.

Java 8

Introduced several significant new features, including lambda expressions and the recent Date & Time API. It also included improvements to security and performance.

Java 11 (LTS)

It included several critical new features, such as the HttpClient API for making HTTP requests, improvements to the garbage collector, and support for Unicode 10.

Java 12-18

These releases have introduced various new features and improvements, including switch expressions, improved error messages, and new APIs for working with collections. 

Application Programs

Java is widely used to create various types of application programs, which are software applications designed to perform specific tasks for users. Java's versatility and platform independence make it an ideal choice for developing a broad range of applications:

• Desktop Applications: Java is used to develop cross-platform desktop applications, such as media players, antivirus software, and office suites. Java's rich set of libraries like Swing and JavaFX provide powerful tools for creating graphical user interfaces (GUIs).
• Web Applications: Java powers many server-side applications that run on the web. Technologies like Java Servlets, JSP (JavaServer Pages), and frameworks like Spring and Struts enable developers to build robust and scalable web applications.
• Mobile Applications: Java is the foundation for Android development, the most widely used mobile operating system. Using Java, developers create mobile apps that run on millions of devices globally.
• Enterprise Applications: Java is a preferred choice for building large-scale, distributed enterprise applications. Java EE (Enterprise Edition) provides a robust set of APIs for building secure, scalable, and transactional enterprise software.
• Games and Embedded Systems: Java is also used in game development and embedded systems. The Java platform's portability allows it to be deployed across different devices and systems.

Why Java Programming Language is Called JAVA?

The Java programming language was originally developed by James Gosling and his team at Sun Microsystems. It was initially called "Oak" after an oak tree that stood outside Gosling's office. However, the name was later changed to "Java," inspired by Java coffee, a type of coffee from Indonesia. The name "Java" was chosen because it reflected the essence of the technology: dynamic, revolutionary, lively, and fun—much like a cup of strong coffee. The name also symbolizes the language's intent to be a "stimulating" and "energizing" tool for developers.

Why Use Java?

Java remains one of the most popular programming languages due to several key benefits:

• Platform Independence: Java's "write once, run anywhere" philosophy allows developers to write code that can run on any device with a Java Virtual Machine (JVM), making it highly versatile and portable.
• Robustness and Security: Java has strong memory management, automatic garbage collection, and extensive exception handling capabilities, which contribute to its robustness. Additionally, Java's security features, such as bytecode verification and sandboxing, make it a secure choice for developing applications.
• Object-Oriented: Java's object-oriented programming (OOP) paradigm promotes code modularity, reusability, and scalability, making it easier to manage and maintain large codebases.
• Extensive Libraries and Frameworks: Java boasts a rich ecosystem of libraries and frameworks that simplify development tasks, ranging from web development (e.g., Spring, Hibernate) to machine learning and big data processing (e.g., Weka, Hadoop).
• Community and Support: Java has a vast and active developer community, which means abundant resources, tutorials, and support are available for developers of all skill levels.
• Performance and Scalability: Java's Just-In-Time (JIT) compiler and optimized runtime performance make it suitable for high-performance applications. Its scalability allows it to handle large, complex systems effectively.

How Java Works?

Java works by using a two-step process: compilation and execution. First, the Java source code is written and saved in files with a ".java" extension. Then, a special program called the Java Compiler translates this source code into a format called bytecode, which is platform-independent.

When you want to run a Java program, a software component called the Java Virtual Machine (JVM) takes over. The JVM interprets or compiles the bytecode into machine-specific code, allowing it to run on any device or operating system with a compatible JVM. This "write once, run anywhere" approach makes Java versatile and popular for creating cross-platform applications, from web apps to mobile and desktop software.

JAVA Terminology

Understanding Java terminology is essential for anyone learning or working with the language. Below are some key terms frequently encountered in Java development, explained with subheadings.

JDK (Java Development Kit)

The Java Development Kit (JDK) is a software development environment used for building Java applications. It includes the Java compiler (javac), the Java Runtime Environment (JRE), and other tools necessary for developing and debugging Java programs. The JDK is essential for writing and compiling Java code.

JRE (Java Runtime Environment)

The Java Runtime Environment (JRE) provides the libraries, Java Virtual Machine (JVM), and other components necessary to run Java applications. It does not include development tools like the JDK but is sufficient for running compiled Java programs. The JRE is what allows Java applications to be platform-independent.

JVM (Java Virtual Machine)

The Java Virtual Machine (JVM) is a part of the JRE that executes Java bytecode, which is the intermediate representation of compiled Java code. The JVM abstracts the underlying hardware and operating system, allowing Java applications to run on any device or OS that has a compatible JVM.

Bytecode

Bytecode is the intermediate code generated by the Java compiler after compiling a Java source file. It is a platform-independent code that can be executed by the JVM. Bytecode allows Java programs to be portable across different platforms without modification.

Class

A class in Java is a blueprint for creating objects. It defines the attributes (fields) and behaviors (methods) that the objects created from the class will have. Classes are the fundamental building blocks of Java applications.

Object

An object is an instance of a class. It represents a real-world entity with state (attributes) and behavior (methods). In Java, everything is an object, and objects interact with one another to perform tasks within a program.

Features of Java

Here are some features of Java:

1. Programmers can create objects with data and functions using Java, an object-oriented language.
    
2. Java programs can be run on any computer with a Java Virtual Machine (JVM) regardless of the hardware or software configuration.
    
3. Manual allocation and deallocation are unnecessary because Java's garbage collector automates memory management.
    
4. A built-in mechanism for handling errors called exceptions enables Java programmes to recover from mistakes and continue running gracefully.
    
5. Java supports concurrent programming, enabling the simultaneous operation of multiple threads.
    
6. Platform independence is maintained while high performance is made possible by Java's just-in-time (JIT) compiler.

Applications Of Java 

Here are some concrete examples of Java applications:

• Java's scalability and robustness make it a popular choice for creating large-scale enterprise applications.
   
• Java can be used to create IoT applications because it offers excellent network connectivity support.
   
• Due to its performance, scalability, and cross-platform support, Java is a popular choice for Big Data technology.
   
• Due to its capacity for handling sophisticated graphics and sound, Java has been demonstrated to be an excellent platform for creating gaming applications.
   
• Because it offers excellent support for network programming and server-side development, Java is frequently used for creating APIs.
   
• Java is a great option for creating messaging applications because it strongly supports messaging systems.
   
• Java offers robust web development support, including web servers.

Also see,  Eclipse ide for Java Developers

Types of Java Applications

Here are some types of Java applications:

Web Development

Java is used to build dynamic and interactive websites and web applications. Popular Java web frameworks like Spring and JavaServer Faces (JSF) simplify web development.

Mobile Apps

Java is a primary language for developing Android apps. Android Studio, the official Android development environment, uses Java extensively.

Desktop Applications

Java's rich graphical libraries enable the creation of cross-platform desktop applications. JavaFX and Swing are commonly used for this purpose.

Enterprise Software

Java is a staple in building large-scale enterprise applications. It's known for its reliability, scalability, and compatibility with various databases and servers.

Game Development

Java is used for developing 2D and 3D games. Game engines like LibGDX and jMonkeyEngine are popular among Java game developers.

Big Data Processing

Hadoop, a widely used framework for processing big data, is built in Java. It's employed for tasks like data analysis and processing massive datasets.

Characteristics of Java

Here are some characteristics of Java:

1. Simple: Java is designed to be easy to learn and use, with a straightforward syntax and a consistent programming model.
    
2. Secure: Java's robust security model allows code from untrusted sources to be safely executed.
    
3. Portable: Java code can be created once and executed anywhere, making switching between hardware platforms and operating systems simple.
    
4. Robust: Java's robust type-checking system and automatic memory management avoid common programming errors like memory leaks and null pointer exceptions.

Functions in Java

Functions are referred to as methods in Java. A method in Java is a group of instructions that carry out a particular function. A method is a small program that the main program can call whenever required. Methods can process inputs, and results can be returned afterwards. They are used to make the code simpler.

Let's see some of the functions of methods in Java

• Reusability: methods can be used in different places in the program making the program looks modular 
   
• Abstraction:  methods can hide the complex details so that code looks redable and easy to understand 
   
• Encapsulation: methods are used to encapsulate the data making the code secure.
   
• Extensibility: methods can be extended to add new functionality

Java Platforms

Java is a general-purpose programming language that provides a variety of platforms for developing and running applications, each with its own set of APIs and tools to meet particular application requirements.

1. Java SE, the familiar environment for developing and running Java applications on desktops and servers, is one of these platforms.
    
2. Suitable for enterprise-level applications is Java EE.
    
3. Software for embedded systems and mobile devices is created using Java ME.
    
4. Rich client applications for multimedia are made using JavaFX.
    
5. Apps for Android-based devices are created using Android.

Java SE 

let's describe it in main points :

• Java SE is known as Standard Edition.
   
• Java SE is the core of the Java programming language.
   
• It is used to develop applications for a wide variety of devices, including desktops, laptops, servers, and mobile devices. 
   
• Java SE includes a comprehensive set of APIs for networking, database access and user interface development to name a few.

Java EE 

let's describe it in main points :

• Java EE also Java Platform Enterprise Edition. 
   
• A platform for creating and deploying enterprise applications.
   
• It includes a set of APIs for web development, messaging, security, and more. 
   
• Mostly it is used by the business to build scalable, reliable and secured web applications.

Java ME 

let's describe it in main points :

• Java ME is a framework also known as Micro Edition. 
   
• It is used for creating and releasing software for smaller devices like mobile phones and set-top boxes. 
   
• Java ME includes a subset of the Java SE APIs and some APIs for specific devices. 
   
• Java ME is used by businesses to develop applications that can be run on a variety of small devices.

JavaFX

let's describe it in main points :

• JavaFX serves as a platform to develop rich internet applications(RIAs). 
   
• RIAs are online applications that communicate with users through a graphical user interface (GUI).
   
• JavaFX includes a set of APIs for GUI development and also has APIs for multimedia and animation. 
   
• Businesses use JavaFX to create e interesting and interactive Rich Internet Applications (RIAs).

Java Frameworks

There are many popular frameworks for Java that developers can use. Several of the most well-liked Java frameworks include

Spring

 A Java framework frequently used to create business applications. Model-view-controller (MVC) architecture, dependency injection, and other features provided by Spring make it possible to build dependable applications.

Hibernate

Java programmers can map Java objects to relational database tables using the Object-Relational Mapping (ORM) framework Hibernate. This streamlines the data persistence process and makes working with databases in Java applications easier.

Struts

A Java web application framework built on the Model-View-Controller (MVC) design pattern. It offers a collection of tools and resources that can be used to quickly and effectively build web applications.

JUnit

A Java testing framework that allows writing and running unit tests for Java code. JUnit comes with various tools and utilities for assessing Java code and ensuring it functions as intended.

These are some of the most well-known and frequently used Java frameworks, though many more can be used for different purposes.

Advantages Of Java

Here are some of the advantages of Java:

1. Efficiency: Java programs can carry out complicated tasks quickly and effectively without burdening the system's resources. Thanks to its scalability and low latency, Java can handle numerous users or requests simultaneously without compromising performance. Java can run complex and large-scale programs smoothly and quickly.
    
2. Cross-platform compatibility: Java-written code can be used without modification on any platform or operating system. This is possible due to the Java Virtual Machine's ability to interpret Java code after it has been compiled into bytecode (JVM). The same Java code can run on a given platform without recompiling as long as the JVM is accessible. It results in developers being able to write code once and run it across various platforms, saving time and effort.
    
3. Safety: Security is a priority in the design of Java. It has features that ensure the code being executed is secure and untainted. It also supports digital signatures and encryption, which helps protect sensitive data in enterprise applications.
    
4. Garbage Collection: Java does not require programmers to manually allocate and deallocate memory because the program automatically controls how much memory newly created objects use. This makes programming simpler and less prone to errors while preventing memory leaks.

Disadvantages of Java

1. Performance Overhead: Java applications can be slower and more memory-intensive compared to applications written in languages like C or C++. The use of the Java Virtual Machine (JVM) introduces an additional layer of abstraction, which can result in slower performance.
2. Verbose Syntax: Java's syntax can be more verbose and require more boilerplate code compared to other modern programming languages like Python or Kotlin. This can make Java code longer and more cumbersome to write.
3. Memory Management: While Java's automatic garbage collection is an advantage, it can also be a disadvantage. The timing and execution of garbage collection can lead to unpredictable performance, especially in applications that require real-time processing.
4. No Support for Low-Level Programming: Java does not support low-level programming features like pointers, which are available in languages like C and C++. This limits Java's use in systems programming and scenarios where direct memory manipulation is required.
5. Limited GUI Development: Although Java offers libraries like Swing and JavaFX for GUI development, these are often considered less modern and flexible compared to other GUI frameworks available in languages like C# or Python. This can limit Java's appeal for developing rich desktop applications.
6. Complexity in Multi-Threading: While Java provides robust support for multi-threading, managing multiple threads can become complex and prone to issues like deadlocks and race conditions, especially for beginners.
7. Dependency on the Java Runtime Environment (JRE): Java applications require the JRE to be installed on the target machine. This dependency can be a limitation in environments where the JRE is not available or where installation of additional software is restricted.

Limitations Of Java

Although Java is a widely used and well-liked programming language, it has shortcomings. These are a few of Java's shortcomings.

1. In Java, giving new meanings to the well-known operators +, -, *, /, etc., is impossible. This implies that you cannot define particular behavior for them when these operators are applied to objects of your classes. Writing expressive and understandable code can be more difficult in some circumstances.
    
2. A virtual machine must first translate Java programs into machine code before they can be executed. The program is then run afterward. This process could make Java programs slower than C or C++, which are compiled straight into machine code. Java programs take longer to start up or complete specific tasks, which, in some cases, can be a performance constraint.
    
3. It is more challenging to write code that generates other code or perform meta-programming tasks where runtime code is developed in Java because of its limited support for macros. This might be a limitation for particular applications that require these features, such as code generators.

It's important to note that many of these restrictions are not specific to Java and that each programming language has advantages and disadvantages.

Simple Program in Java

Here's a simple Java program example:

This code asks the user to type their name before displaying a customized greeting.

import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Please enter your name: ");
        String name = input.nextLine();
        System.out.println("Hello, " + name + "!");
}
}

Output:

Please enter your name: John
Hello, John!

Explanation:

This code is a straightforward Java program that asks users for their names before addressing them by name. Next, the "Please enter your name:" string is printed to the console using the "print" method. The next step is to read a line of text the user enters and store it in the String variable "name" using the Scanner class' "nextLine" method. The program then prints a customised greeting to the console using the user's name, entered earlier, using the "println" method.

Read more, how to run java program

Frequently Asked Questions

What are the three types of Java?

Standard Edition (SE), Enterprise Edition (EE), and Mobile Edition (ME) are the three main editions of Java (Micro Edition). Java EE builds on Java SE for large-scale enterprise applications, Java ME is for building applications on small devices with limited resources, and Java SE provides the core language and libraries for desktop and server-side applications.

How to do Java programming?

To do Java programming, you basically need an IDE or a text editor to write the code and then execute it using the JVM (Java virtual machine) but before that, the code needs to get compiled using the Java compiler.

Where do I write Java code?

You can write Java code using any text editor, but it is preferred to switch to some IDEs like Eclipse or Visual Code Studio as they provide many features that make programming easier. 

Conclusion

We've discussed a lot of crucial facets of the Java programming language in this article. It also emphasizes why it is such a popular programming language. As we've seen, Java is a robust language for creating complex applications because it includes advanced features like inheritance, polymorphism, and multithreading. We reviewed its main advantages, drawbacks, and applications in various fields. In conclusion, this article thoroughly overviews Java, covering everything from its fundamental topics to more complex subjects.