LoadTimeWeaver which uses reflection to delegate to an underlying ClassLoader with well-known transformation hooks. The underlying ClassLoader is expected to support the following weaving methods (as defined in the LoadTimeWeaver interface):

• public void addTransformer(java.lang.instrument.ClassFileTransformer): for registering the given ClassFileTransformer on this ClassLoader
• public ClassLoader getThrowawayClassLoader(): for obtaining a throwaway class loader for this ClassLoader (optional; ReflectiveLoadTimeWeaver will fall back to a SimpleThrowawayClassLoader if that method isn't available)

Please note that the above methods must reside in a class that is publicly accessible, although the class itself does not have to be visible to the application's class loader.

The reflective nature of this LoadTimeWeaver is particularly useful when the underlying class loader implementation is loaded in a different class loader (such as the application server's class loader which is not visible to the web application). There is no direct API dependency between this LoadTimeWeaver adapter and the underlying ClassLoader, just a 'loose' method contract.

This is the LoadTimeWeaver to use in combination with Spring's TomcatInstrumentableClassLoader .