Dynamic loading of Java classes at runtime provides tremendous flexibility in the development of enterprise systems. It provides for the basis of "application servers", and allows even simpler, lighter-weight systems to accomplish some of the same ends. Within Java, dynamic loading is typically achieved by calling the forName method on the class java.lang.Class; however, when Class.forName is naively called from within an Extension, strange errors can occur. This paper describes why those errors occur, and how Java2 provides two facilities, one a modification to the forName syntax, and the other, called the "Thread context ClassLoader", to avoid them. This paper assumes you are passingly familiar with Java Reflection, and have at least a general idea of what Java ClassLoaders are and how they are used within Java code.
Keywords:Java ClassLoaders Extensions Threads
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