Developers are facing a very rapid evolution of new products and technologies. In addition, they have to cope with increasing customer requirements. Competitors must provide new products releases in decreasing time frames without hampering quality. Thus, the question arises how these different forces might be balanced.The right answer is: If technological evolution and requirements are changing rapidly, at least the underlying software architectures should remain stable. Architectures must be built with future changes and extensions in mind. On one hand, Multi-tier Architectures might be introduced for this purpose. This helps for a separation of concerns, but alone it is not sufficient. To design for change and evolution a component-based approach is the right choice. Components represent fundamental units of distribution and functionality. They define hooks for future change and extension. This is the reason why the Java Beans technology was introduced by JavaSoft. However, JavaBeans are a perfect solution for building desktop-centered user interfaces, but they do not help for deploying functionality on the server-side. Therefore, JavaSoft has recently provided the Enterprise JavaBeans Specification. Despite of their names, JavaBeans and Enterprise JavaBeans are different technologies addressing different tiers of multi-tier architectures. The tutorial will give an in-depth introduction of both technologies. It will also compare the technologies with the alternatives provided by Microsoft WindowsDNA.