Java is an object-oriented programming language and a software development platform for creating and launching secure, scalable applications for different systems. Its runtime environment, the Java Runtime Environment (JRE), is a complete ecosystem where you can program and execute apps that will run on any device with a Java Virtual Machine (JVM).
Guided by its "write once, run anywhere" motto, with Java, you can easily develop software for desktop computers, mobile devices, as well as enterprise-level systems. It's one of the most robust and reliable platforms due to its extensive libraries, powerful error handling, and advanced security features.
Nowadays, most modern software is developed using Java, and this platform has a big and engaged community that contributes to improvement, learning materials, and best practices. Java, as a free and open-source project, is also regularly updated, and there are numerous development tools and frameworks you can use to adjust to your specific use case.
Why should I download Java?
Anyone working on modern software should be acquainted with Java and its runtime environment, JRE. This is mainly because the applications you build with it can operate across multiple systems and usually only require minimal changes. Using bytecode to compile the apps, which is then executed by the Java Virtual Machine (JVM), allows this solution to live up to its philosophy of "Write Once, Run Anywhere”.
Since you can download Java for free, it's the perfect choice whether you're just starting out or are a seasoned professional, and with Java Runtime Environment (JRE), you get everything you need to run Java apps. The package includes JVM (Java Virtual Machine), which is an engine that allows compiling and then running bytecode as machine code as well as core class libraries like java.lang, java.util, and java.net, used by almost every Java application. Having this environment is crucial as Java relies on it to deliver consistent behavior, no matter the hardware or operating system. Minecraft, Jenkins, and LibreOffice all use Java for their backbones, just to name a few.
Java and JRE are also integral parts of developing server applications, banking tools, ERP platforms, and other solutions needed in business and enterprise settings. Java not only enables you to build those things out but also makes it possible for all this software to run smoothly, securely, and reliably. With Java, you can also utilize GUI libraries like Swing and JavaFX, which deliver objects and patterns that are commonly found in desktop apps for various purposes.
Everything you create with Java has a backward compatibility component, so even solutions developed years ago and legacy apps are still supported on the newest versions of JRE. The most modern editions include Java Platform Module System (JPMS), where you can utilize modular runtimes and include only those components and libraries you require. Use that to save memory usage and speed up the performance of your applications. There is also a solution called Java Development Kit (JDK), where you get various tools for compiling and debugging your work.
Is Java free?
While Java is usually a free platform, it also depends on how you plan to use it and which tool you will work on. You don't need to pay anything if you're a personal user. For commercial purposes, Oracle requires a subscription (Java SE) if you want to have updates or support for Java 11 or later.
However, you can always access Java through OpenJDK, which is free and open-source, and there are no licensing fees. There are also replacements for the official Oracle distributions that remain free no matter what.
What operating systems are compatible with Java?
You can download and use Java and its runtime environment on various systems, as the whole idea behind the technology is that it's platform-independent. The supported operating systems are Windows (7, 8, 10, 11 in 32- and 64-bit versions), macOS (10.13 or higher), Linux (all major distributions), as well as Solaris and BSD systems. JDK and JRE are also compatible with Docker containers, CI/CD environments, and Embedded devices (ARM architecture).
For anyone who wants to use Java to learn programming or run apps, there are a number of free distributions you can use, and they include Eclipse Adoptium (Temurin), Amazon Corretto, Azul Zulu, and BellSoft Liberica.
What are the alternatives to Java?
OpenJDK is a great option for anyone who wants to use Java for multiple different purposes but doesn't want to have any licensing fees. It's the official, open-source implementation of Java Standard Edition (SE) and gives you access to the entire runtime environment. A lot of popular apps and enterprise-level solutions are using it instead of JRE, as OpenJDK is distributed under the GPL license, where you can not only use but also modify the source and share it on your own. It has all the standard tools like JVM, libraries, and development utilities you'll find in Oracle's versions. OpenJDK is also constantly supported and improved, and supports backward compatibility, so it remains a great choice for a large base of users and has a very dedicated and active community.
If you're looking for a different technology altogether, then .NET Framework is Microsoft's runtime platform for apps built with C#, F#, and VB.NET, but keep in mind that this alternative is mostly targeted at creating solutions for Windows machines. There are also newer versions like .NET 6/7/8 created as open-source projects with which you can build cross-platform apps, and they also have improved performance and modularization as well as support working with containers.
Another option for working with .NET but utilizing it for different platforms is called Mono. It's an open-source implementation of the .NET Framework that works on Windows as well as on macOS, Linux, and mobile platforms. You can also use Mono for game development and scripting, as game engines such as Unity are largely based on it. As a solution from MIT University, Mono is available for free.
