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There are a number of interfaces where the validator can implement one or more of them; Since the agents need to work with earlier java versions, unfortunately default methods in the interfaces are not possible so instead there are different interfaces you can implement depending on the functionality you need. Our strategy has been to create additional interfaces with new methods for new functionality to ensure that all existing implementations with with the with the existing interfaces.
At runtime, we detect which ones are implemented and thus what amount of functionality the validator has available.
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