Java’s purpose is to provide developers with a tool that can be utilised in applications such as web and app development, mobile OS creation, and game design. Its standout feature, the "write once, run anywhere" (WORA) capability, allows Java-coded programs to operate on any device equipped with a Java virtual machine (JVM), fostering cross-platform compatibility. 

Java is primarily used in enterprise-scale applications, and stands out for its stability and security features. Industry leaders such as Google, Amazon, and Netflix rely on Java to manage their back-end services such as web applications, cloud applications, machine learning environments, and the Internet of Things. Moreover, its stronghold in Android app development persisted for years as the default language, further cementing its relevance. 

On a larger scale, Java plays an essential role in driving modern internet infrastructure due to its robustness, scalability, and performance. It serves as the basis for most handheld devices, gaming platforms, and navigation systems. Java is as a key technology in the field of IT development, useful for creating standalone, server-side, and web-based applications.