Nomin by default caches mapped instances. It allows to improve performance in case of frequently repeating values to be mapped. Also caching mapped objects serves as a cycle detection mechanism to prevent infinite loop in case of bidirectional references.
Caching can be disabled. Actually this is required in rare cases. For example you would like to create a new object instance each time you call NominMapper.map(...) instead of getting a cached one. Also there is an interesting case when disabling cache is useful, please refer org.nomin.functional.MappingCasesTest.
To enable or disable caching just call the corresponding method on org.nomin.NominMapper as follows:
nominMapper.enableCache(); // or nominMapper.disableCache();