The Technologies of Java

ENT, August 12, 1998

Virtual Machine (VM). A key differentiator between Java and other languages, the VM isolates Java code from platform differences. VMs are bundled with popular browsers and operate outside the browser as well. The VM can be also a trouble spot, because code that runs on one vendor's VM will not necessarily run identically on another's. Current VM incompatibilities have spawned the catch phrase "write once, test everywhere."

Component Model. The JavaBeans component model enables design time access to objects, object persistence and integration with rapid application development (RAD) environments. Bridges from JavaBeans to Component Object Model (COM) and Common Object Request Broker Architecture (CORBA) are available.

Class Libraries. At least three popular class libraries are available for simplifying Java development. AFC (Microsoft) and JFC (Sun) are both pure Java implementations. WFC (also Microsoft) is a Windows-specific class library that uses COM rather that JavaBeans as its component model and directly calls Windows API functions from thin Java wrappers.

Enterprise JavaBeans Specification. The relatively new Enterprise JavaBeans specification describes the interfaces for enterprise Java services, such as transaction processing, data binding, message queues and remote management. Virtually all enterprise vendors except Microsoft endorse Enterprise JavaBeans to some degree.