"JavaBeans is the platform-neutral, component architecture for Java. It's the ideal choice for developing or assembling network-aware solutions for heterogeneous hardware and operating system environments--within the enterprise or across the Internet. In fact, it's the only component architecture you should consider if you're developing in a Java environment." - http://java.sun.com/beans/
JavaSoft have developed a uni-directional ActiveX Bridge for JavaBeans (Java components serving COM/ActiveX clients)