Java is a powerful, object-oriented programming language created by Sun Microsystems (now owned by Oracle). It's designed to be platform-independent, meaning code written as "Java bytecode" can run on any device with a Java Virtual Machine (JVM), from servers to mobile phones. This principle is known as "Write Once, Run Anywhere" (WORA).

For web hosting, Java is crucial for running dynamic, enterprise-level applications. When you see a website with complex features like banking portals, e-commerce systems, or large-scale content management, there's a high chance it's powered by Java on the server-side.

To use Java for your website, your hosting plan must support it. Look for these key features:

• Java Servlet Support: Allows the server to handle dynamic web requests.
• JSP (JavaServer Pages): Enables embedding Java code directly into web pages for dynamic content.
• A compatible Application Server: Such as Apache Tomcat, Jetty, or JBoss, which hosts and executes your Java applications.

Choosing a host with Java support is essential if your site relies on Java-based frameworks like Spring or Struts. Without it, your application simply won't work. Ensure your hosting environment matches the specific Java version your software requires for optimal performance and security.

In summary, Java provides the robust, scalable backbone for many advanced web services. Selecting a hosting provider with solid Java infrastructure is the first step to deploying reliable, high-performance web applications.