Java Tutorial: What is Java?

A plethora of high-level programming languages is available out there. One of the most widely used high-level, general-purpose programming languages is Java. It is a widely-used object-oriented programming language, which means it is based on the concepts of “objects,” which are basic runtime entities. It is a programming language and a computing platform for developing robust applications.

Well, if you are a newbie to this language and want to explore more about the same, you have landed on the right page. This blog post will familiarize you with the Java language and the computing platform. Also, you will learn the features and various components of Java. So, let us get started without further ado!

What is Java?

It is a general-purpose, high-level, class-based programming language. It follows the principle of Write Once, Run Anywhere (WORA). Meaning that once you write and compile a Java program, you can run it on any other Java-enabled machine without recompiling it. This is because the Java programs are compiled into bytecode that can run on any Java Virtual Machine (JVM). The syntax of Java is closely similar to C and C++ .

Moreover, it is an object-oriented programming language that follows all four concepts: polymorphism, abstraction, encapsulation, and inheritance. However, it is not a pure object-oriented language.

The reason is Java has primitive data types, such as byte, short, int, long, char, float, double, and boolean, which are not objects. Along with a programming language, Java is also a computing platform. This platform allows developers to write and run Java programs efficiently. It primarily comprises an execution engine, compiler, and set of libraries.

History

James Gosling, Mike Sheridan, and Patrick Naughton, in June 1991, began developing the Java language project. Originally, they designed this language for interactive television. However, it was too advanced for the television industry at that time.

The developer, Games Gosling, initially named the language 'Oak.' He got this idea from an Oak tree that was present in front of his office.  After that, developers named it Green. Finally, Games Gosling renamed the language Java, a type of coffee from Indonesia. While creating this language, the developers had the following five principles:

• The language must be simple, familiar, and object-oriented.
• It must be powerful and secure.
• It must be architecture-neutral and portable.
• The language must execute with high performance.
• It must be threaded, dynamic, and interpreted.

In 1996, Sun Microsystems publicly released the first version of Java, Java 1.0. After that, the company released many versions of Java with additional and advanced features. However, in 2009-10, Oracle Corporation acquired Sun Microsystems. Today, the Java language is maintained and owned by the Oracle Corporation. The latest version of Java is Java 18, as of March 2022.

Features

The following are the salient features of Java:

• Object-Oriented: Though Java is not purely an object-oriented programming language, it supports all four basic concepts of OOPS, namely polymorphism, abstraction, encapsulation, and inheritance.
• Compiled and Interpreted: Java is both compiled and interpreted language. A Java compiler (javac) compiles source code into bytecode. Later, Java Virtual Machine executes that bytecode on any Java-enabled machine.
• Platform-Independent: As discussed earlier, Java follows the principle of WORA, i.e., Write Once, Run Anywhere. You can write and compile a Java program on one machine and run it on another Java-enabled machine. Therefore, Java is platform-independent. Generally, the Java compiler converts a Java program into bytecode, and that bytecode can run on any Java-enabled platform.
• Architecture-Neutral: This language is architecture-neutral because there are no implementation-dependent features. For instance, all the primitive data types have fixed sizes. The size of any primitive data type does not change, irrespective of the system architecture.
• Multi-Threaded: Multi-threading implies the execution of two or more parts of the same program simultaneously for maximum utilization. Java is a multi-threaded language.
• High Performance: Java is a high-performance language because its architecture reduces overhead during runtime. Also, it comes with a just-in-time (JIT) compiler that compiles code during the execution of a program rather than before the execution.
• Dynamic: Java is a dynamic language. You can load classes in a Java program as and when required.

Advantages and Disadvantages

Let us now shed light on some remarkable advantages and disadvantages of Java.

Advantages

• Java is a simple-to-use and straightforward language.
• It supports automatic garbage collection and memory allocation.
• Since there is no explicit pointer in Java, it is a secure programming language.
• It is a robust language because it uses strong memory management.

Disadvantages

• Java is a slow language since it consumes a lot of memory.
• It is a bit more expensive than other languages due to its higher processing and memory requirements.
• You can control Java's automatic garbage collection. And it does not provide functions like free() or delete () to free memory.

What is Java Used For? Top 17 Java Applications

Java is used for the development of the following applications:

1. Gaming Applications

Today, many indie game development companies leverage Java to create video games and mobile games. In fact, many popular games, including Minecraft, Asphalt 6, Tetris, Space Invaders, and Mission Impossible III, are developed in Java. Java’s open-source and powerful 3D game engine, JMonkeyEngine, makes it a popular choice for video game development.

2. Web-Based Programs

Initially, Java became a popular programming language for web development because of the ability of Java applets to run in a browser. It is well-known as a server-side language for creating responsive web applications and websites.

However, the use of Java applets for developing web applications is a pretty old idea. Today, a galore of Java frameworks are available out there, such as Spring, Hibernate, Apache Hadoop, JavaServer Faces, and Struts. Amazon, Broadleaf, Aliexpress, LinkedIn, and Wayfair are popular websites developed using Java.

3. Internet of Things (IoT) Applications

Java is an ideal language for developing IoT applications because of various reasons, as follows:

• The first reason is that Java is platform agnostic, i.e., you need to write code only once and run it on any system that supports Java.
• Another reason for Java to be an ideal choice for IoT applications is its adaptability and flexibility, as it is used in developing a variety of applications, such as web-based, desktop, mobile, and gaming.
• Furthermore, it becomes easier to integrate multiple technologies while working with Java than with any other language.

For all the reasons above, Java has applications in embedded electronics, medical gadgets, and automotive navigation systems.

4. Big Data Applications

Though Python is the most preferred language for big data, many programmers and organizations also prefer Java. The reason is that many big data tools , such as Hadoop, Spark, Storm, and Deeplearning4j, are developed in Java.

Moreover, some outstanding features of Java, such as automatic garbage collection, stack provision system, and memory distribution, make it a great choice for building big data applications. Also, Java has a huge community and gets strong support for big data.

5. Android Apps

The official language for developing Android applications is Java. Most Android applications we use today, such as Spotify and Twitter, are developed using Java. The most popular Android IDE, Android Studio, leverages Java to build Android applications. More interestingly, the Android operating system is developed in Java.

So, if you have profound knowledge and hands-on experience with Java, you can easily get started with Android development.

6. Desktop Applications

Since its inception, Java has been an ideal language for building desktop applications. More specifically, it is widely used for creating desktop GUI applications. Popular Java libraries, such as AWT, Griffon, JavaFX, and Swing, provide Java developers with pre-built components, such as buttons, menus, text fields, and many others, to facilitate the development of desktop applications.

7. Distributed Applications

A distributed application has either one or more clients, remote or local, communicating with one or more servers on multiple machines over a network.

Java Intelligent Networking Infrastructure (JINI), a distributed computing environment from Sun Microsystems, simplifies the development of distributed applications.

8. Enterprise Development

Java Enterpise Edition (Java EE) is dedicated to developing enterprise applications. This edition has APIs and runtime environment features for writing and running enterprise software applications, web services, and network tools. In addition, Java's high performance and speed make it a suitable choice for building enterprise software applications. Customer relationship management (CRM) tools and Enterprise Resource Planning (ERP) systems are examples of enterprise applications developed in Java.

10. Scientific Applications

Java is the most preferred programming language when developing applications involving mathematical operations and scientific calculations. The robust features of Java have made it possible to develop scientific applications that solve real-world problems using mathematics.

Moreover, Java provides a fast, highly portable, and secure environment for scientific applications. One of the most popular programming platforms, called MATLAB (Mathematics Laboratory), leverages Java to develop the front-end and back-end of scientific applications. JSP (Java Server Pages), servlets, and struts are intended for the front end, while core Java with servlets can be used for the back end.

11. Embedded Systems

Embedded systems or integrated systems combine several small computing units together to carry out specific functions for larger systems. Many people use embedded systems unknowingly. Some examples of embedded systems used are a motor system, eCommerce, networking, and mobile computing.

Java is the primary language for the development of embedded systems. As Java is fast, it is extremely helpful while using low-powered and low-speed processors.

12. Web Servers and Application Servers

A web server is a hardware and software that leverages various communication protocols, such as HTTP, to respond to user requests with the desired web pages. It makes websites run by storing, processing, and displaying web content to users.

An application server manages the installation, operation, and hosting of associated services and applications for organizations, IT services, and end-users.

There are a lot of web servers and application servers developing Java. Java's web servers include Apache Tomcat, Rimfaxe Web Server (RWS), Apache HTTP Server, Simple, Jo!, Resin, and Adobe JRun. Application servers developing using Java are JBoss EAP, WebSphere, WebLogic, GlassFish, and WildFly.

13. Software Tools

Software tools are a suite of computer programs that help developers in designing, building, testing, and maintaining software applications. NetBeans and Eclipse are popular software tools developed in Java. They are IDEs that bring several developer tools under one roof to facilitate the development process.

14. Trading Applications

Along with the web and software development industry, Java has paved its way in the trading industry. It is used for developing various trading applications. Murex, a trading and risk assessment platform, is developed in Java.

15. J2ME Applications

J2ME stands for Java 2 Micro Edition. It is a technology that lets developers leverage Java and other required technologies to build applications for mobile wireless information devices, such as cellular phones and personal digital assistants (PDAs).

16. Server Applications in Financial Industry

Financial companies leverage a variety of software programs to carry out their day-to-day activities, such as data processing, writing settlements, and many others. Most of the software programs used in this industry are developed in Java. The reason is that Java is the most preferred language for creating server-side applications. Popular financial institutions like Goldman Sach, Barclays, and Citi groups leverage Java-based software programs.

17. Artificial Intelligence

Artificial Intelligence (AI) is one of the breakthrough technologies. It is a branch of computer science that deals with developing applications that mimic human intelligence. And Java is one of the best languages for developing AI projects. Its features, such as ease of debugging, better user interaction, ease of coding, and many others, make it a preferred language.

Components of Java Programming

Java has three primary components: JRE, JDK, and JVM. Let us discuss each of these components in detail below.

1. Java Development Kit (JDK)

Java Development Kit (JDK) is a distribution of Java technology and one of the core components of Java programming. It is a software development environment comprising standard libraries and tools developers use to build Java applications and applets. Many people get confused between JDK and JRE.

JRE is sufficient if you wish to run Java programs on your system. However, you need JDK with JRE if you wish to develop a fully-functional Java software application. JDK includes the following tools:

The aforementioned tools are used to build and run Java applications.

• A Java source code is created in a text editor or an IDE.
• The Java compiler javac compiles the source code. Later, the Java interpreter java executes the compiled source code.
• You can check for errors in the source code by debugging it using the Java debugger jdb .
• The compiled Java program is converted into source code with the help of javap .

2. Java Runtime Environment (JRE)

Java Runtime Environment (JRE) is a set of components required to run a Java program on a computer. It is a part of JDK and consists of loader classes, libraries, and JVM. JRE is a mandatory component of Java programming if you wish to develop and run Java programs. It comprises of:

• Java Virtual Machine(JVM) : This interprets the intermediate Java bytecode and generates output.
• Runtime class libraries: These are a set of core class libraries that are required for the execution of Java programs.
• User interface toolkit : Toolkits that support varied input methods for the users to interact with the application program. For example, AWT and Swing.
• Deployment technologies : JRE comprises of following key deployment technologies:
• plug-in : Enables the execution of a Java applet on the browser.
• Web Start : Enables remote-deployment of an application.

3. Java Virtual Machine (JVM)

Java Virtual Machine (JVM) is a virtual machine or a runtime engine that provides an environment to run Java applications. It is part of JRE. Moreover, it converts bytecode from the Java compiler into machine code. It comprises various libraries, tools, and frameworks. In addition, JVM has a built-in just-in-time (JIT) compiler, which compiles the source code during its execution.

Types of Java Platforms

There are four different types of Java Platforms, as follows:

• Java Platform, Standard Edition (Java SE)

The API of Java provides all the functionality of Java programming. This type of platform defines everything from the fundamental types and objects of Java programming to high-level classes. Moreover, this platform is ideal to use for networking, database access, graphical user interface (GUI) development, and XML parsing.

• Java Platform, Enterprise Edition (Java EE)

This platform, Java EE, is built on top of Java SE. It provides an API and a robust runtime environment for developing secure, highly scalable, large-scale, reliable, and multi-tiered network applications.

• Java Programming Language Platform, Micro Edition (Java ME)

The Java ME platform provides an API and a small-footprint virtual machine for running Java applications on small devices like mobile phones. The API of this platform is the subset of the Java SE API.

• Java FX

Java FX is a robust platform for creating feature-rich internet applications using the Java FX Script. It is a statically-types declarative language. The Java compiler converts programs written in Java FX script into bytecode, and the JVM can run that bytecode.

Why Should You Learn Java?

Let us throw light on some reasons for learning Java.

• Easy to Learn

Java is a simple programming language that is easy to learn if you are familiar with C and C++. This is because Java has analogous syntax to C and C++. Also, James Gosling designed Java by keeping five core principles in mind.

• Widely Used Programming Language

Java is a versatile language widely used for building various applications, from desktop applications to games. It is, therefore, among the programming languages that are most frequently used.

• High Salaries

As Java is a widespread and popular language, companies and organizations are seeking individuals who are proficient and skilled in Java. They offer attractive packages to professionals having expertise in Java.

• Flexible Language

The WORA feature of Java and portability and scalability make it a more flexible language. It enables an already compiled Java code on one machine to run directly on any other Java-enabled machine .