What is Java?
Learn why Java remains such a popular development platform and how it accelerates projects and supports a wide range of emerging technologies.
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What is Java?

Java is a widely used object-oriented programming language and software platform that runs on billions of devices, including notebook computers, mobile devices, gaming consoles, medical devices and many others. The rules and syntax of Java are based on the C and C++ languages.

One major advantage of developing software with Java is its portability. Once you have written code for a Java program on a notebook computer, it is very easy to move the code to a mobile device. When the language was invented in 1991 by James Gosling of Sun Microsystems (later acquired by Oracle), the primary goal was to be able to "write once, run anywhere."

It's also important to understand that Java is much different from JavaScript. Javascript does not need to be compiled, while Java code does need to be compiled. Also, Javascript only runs on web browsers while Java can be run anywhere.

New and improved software development tools are coming to market at a remarkable pace, displacing incumbent products once thought to be indispensable. In light of this continual turnover, Java’s longevity is impressive; more than two decades after its creation, Java is still the most popular language for application software development—developers continue to choose it over languages such as Python, Ruby, PHP, Swift, C++, and others. As a result, Java remains an important requirement for competing in the job market.

IBM offers a simple tutorial to learn Java for building a scalable web application using Kubernetes and the Java platform.

How Java works

Before exploring the reasons for Java’s enduring popularity, let’s review what Java is in more detail and its importance for enterprise application development.

Java is a technology consisting of both a programming language and a software platform. To create an application using Java, you need to download the Java Development Kit (JDK), which is available for Windows, macOS, and Linux. You write the program in the Java programming language, then a compiler turns the program into Java bytecode—the instruction set for the Java Virtual Machine (JVM) that is a part of the Java runtime environment (JRE). Java bytecode runs without modification on any system that supports JVMs, allowing your Java code to be run anywhere.

The Java software platform consists of the JVM, the Java API, and a complete development environment. The JVM parses and runs (interprets) the Java bytecode. The Java API consists of an extensive set of libraries including basic objects, networking and security functions; Extensible Markup Language (XML) generation; and web services. Taken together, the Java language and the Java software platform create a powerful, proven technology for enterprise software development.

Why Java matters

If you are an enterprise application developer, you already know what Java is, and it’s likely that your organization already has thousands, even millions, of lines of production code written in Java. You will likely need some level of Java expertise to allow you to troubleshoot, maintain, and upgrade your existing codebase.

However, it would be a mistake to view Java only in terms of legacy applications. The Java language forms the heart of the Android operating system, which powers by far the largest share of the world’s smartphones. Java is also among the most popular languages for machine learning and data science applications. Its robustness, ease of use, cross-platform capabilities and security make Java the language of choice for internet solutions in many enterprise shops.

In particular, Java technology is an ideal framework for developing web applications, the foundation for a digital business in any industry. Java application servers are web containers for Java components, XML, and web services, which interact with databases and provide dynamic web content. Java application servers form a stable deployment environment for enterprise applications with capabilities such as transaction management, security, clustering, performance, availability, connectivity, and scalability.

Technical benefits

When it comes to choosing a programming language and environment for your next enterprise application, there are solid technical reasons to consider Java, including interoperability, scalability, and adaptability.

The core philosophy behind its creation—interoperability across disparate devices—remains the strongest argument for favoring Java for new enterprise applications. Java’s object-oriented architecture allows you to create modular programs and reusable code, shortening development cycles and extending the longevity of enterprise applications.

Platform scalability is a key attribute of Java. With Java, you can use one single system across a broad range of use cases. Existing desktop applications can be easily adapted to run on smaller devices that have limited resources. You can also migrate applications from mobile to desktop, developing business apps for the Android platform and then integrating them into your current desktop software, bypassing lengthy and expensive development cycles.

Java also wins points with strategic planners for its ability to adapt to new use cases. For example, Java is widely considered to be an ideal platform for the Internet of Things (IoT). The typical IoT application interconnects a large number of disparate devices, a task that is greatly simplified by the fact that billions of devices run Java. Furthermore, Java’s extensive ecosystem of developers is constantly developing and sharing new libraries with functionality specifically targeted at IoT application development.


Business benefits

The technical arguments for Java are compelling, but the business reasons to choose Java are equally strong: a large talent pool, a short learning curve, and a wide range of integrated development environments (IDEs).

As more companies use connected devices, machine learning algorithms, and cloud solutions, the demand for skilled developers continues to grow. Many analysts foresee a scarcity of senior-level programmers in the near future, making it difficult to staff new software initiatives. Demand for mobile app developers could soon easily exceed the available supply.

The large talent pool of Java developers constitutes a compelling reason to base major software initiatives on Java. When staffing managers post job openings for Java developers, they can expect to receive many qualified resumes and fill those positions relatively quickly. Managers can also draw on contract resources to supplement in-house staff for specific tasks without adding headcount.

In addition to senior-level developers, major software initiatives also require large numbers of junior contributors. While Java remains a popular introductory programming language in university computer science curriculums, many graduates lack the proficiency to be productive on day one. Java is easier to learn and master than many other programming languages, leading to a shorter learning curve and faster ramp-up to productivity. Java’s extensive online community of developer forums, tutorials, and user groups helps beginners get up to speed rapidly and provides seasoned programmers with effective, proven problem-solving tools.

In the area of programming tools, Java offers a range of IDEs. Experienced Java developers can quickly ramp up on a new environment, which frees development managers to choose the IDE that best fits the type of project, budget, development methodology and programmer skill level. Many seasoned Java programmers think of NetBeans, Eclipse, and IntelliJ IDEA as the top three IDEs for enterprise application development. But there are cases where a more lightweight IDE such as DrJava, BlueJ, JCreator, or Eclipse Che is the best choice.

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Take the next step

IBM® WebSphere® Application Server is a flexible, secure Java server runtime environment for enterprise applications. Deploy and manage applications and services regardless of time, location, or device type. Integrated management and administrative tools provide enhanced security and control, and support for multicloud environments lets you choose your deployment method. Continuous delivery capabilities and services help you to respond at the speed of your business needs.

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