public void addAll(ClassMappings additionalClassMappings) {
        Map<String, ClassMap> newMappings = additionalClassMappings.getAll();
        for (Entry<String, ClassMap> entry : newMappings.entrySet()) {
            ClassMap result = classMappings.put(entry.getKey(), entry.getValue());
            failOnDuplicate(result, entry.getValue());
        }
    }
Internal class that determines the appropriate class mapping to be used for
the source and destination object being mapped. Only intended for internal
use.
core/src/main/java/com/github/dozermapper/core/classmap/ClassMappings.java