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IntroductionThe Microsoft Virtual Machine for Java (Microsoft VM) supports integration between Java and the Component Object Model (COM), which is the protocol underlying the Microsoft® ActiveX® platform, Automation, and Object Linking and Embedding (OLE). With Java/COM integration, you can give your Java program access to any software component that supports COM, including thousands of ActiveX controls and Automation objects. Java/COM integration is available at two levels, corresponding to the dual-interface nature of the ActiveX Automation model. At the highest level, ActiveX controls are converted directly to JavaBeans components (Beans) by the Microsoft VM, and Beans are converted to ActiveX controls. The type mapping for parameters is done automatically in this case, based on the standard IDispatch types used by all ActiveX controls to communicate with their containers. On the other hand, since ActiveX controls are dual-interface objects, they can also be accessed by their vtable methods. This is how C programs typically access these controls and what is referred to as low-level Java/COM integration in this article. This mode of access is particularly useful when you need to marshal data types that are not handled by IDispatch between Java and COM objects. New FeaturesIf you have used earlier versions of the SDK for Java and Visual J++, you might be interested to learn about several new features that can make it easier (or more efficient) to accomplish certain tasks that involve COM objects. These tasks previously required the use of javatlb, which has been replaced by the jactivex tool (called jcom in previous releases):
The following topics are available in this article:
You can find more information about COM in the Component Object Model Specification that is included in the Win32 Software Development Kit.
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