What Is Java?
Java, which was code named “Oak” and “Green” during initial development, came on the scene in May 1995. Many saw it as a successor to or evolution of C/C++ since it borrowed much of the same syntax while introducing new concepts that made coding safer and easier. One of the primary tenets of Java was, and still is, the idea that programmers should be able to “write once, run anywhere.” Instead of compiling to separate executables for different target platforms, Java code is compiled to a single JAR file that runs on any Java-supporting system.
This is made possible by the Java Virtual Machine (JVM). The JVM reads the JAR file (which is a collection of Java-specific instructions), compiles it to platform-specific instructions at runtime, then executes the app. This process is aptly named just-in-time compilation. Learn more in our overview of the JVM.
So how is Java used in the real world?
- Android apps — While other languages can be used, Java is the official language of Android app development, which means fastest performance and most native experience.
- Desktop apps — Java is perhaps the easiest way to create cross-platform software these days. Swing used to be the UI toolkit of choice for Java developers, but if you’re just starting out, skip it and learn JavaFX or SWT instead. You’ll thank yourself later.
- Enterprise systems — Industries with high-volume data processing (e.g. banking, financial trading, etc.) tend to use Java for non-legacy systems because it’s fast, portable, easier to maintain, and less prone to the kinds of catastrophic bugs that are common in lower-level languages.
- Embedded systems — Some areas of the embedded space now rely on Java. Examples of embedded systems include digital watches, factory controllers, traffic lights, microcontrollers, hybrid vehicles, and more recently, Internet of Things devices.
- Scientific research — While data processing, computing, modeling, and simulations are often done in languages like MATLAB and Python, Java is commonly used for more complex tasks like natural language processing and artificial intelligence.
When to Use Which Language?