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An IdPModule is found through the Java Services API, which relies on a special file in META-INF to identify the possible implementations of an interface. The tools that operate on IdPModules use the ServiceLoader class to locate the implementations and instantiate the interface to perform work. There are no other inherent restrictions on how modules may be implemented, but there are classes provided that simplify the work involved to simply defining a few properties and embedding various files in a jar on the IdP's classpath.
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