Plugin Shmuggin - Java's Sweet Spot is in Backend/Server Apps
The original intent for Java was as an applet technology for the browser, but those apps have played a minor role in the use of Java as a programming language. Developers have for a long time moved way beyond that and toward web applications - where the java application is deployed in an appserver such as Tomcat, JBoss, among many others. Using frameworks such as Struts, Spring, and Hibernate, give developers great flexibility when designing scalable applications. Java code for non-trivial applications lends itself to well organized packages.
I have routinely developed enterprise applications on Windows platforms and easily - without code changes - deployed the same applicaiton on Linux or other OS platforms.