### Question:
GenericCollectionTypeResolver { public static Class<?> getMapKeyParameterType(MethodParameter methodParam) { return getGenericParameterType(methodParam, Map.class, 0); }  static Class<?> getCollectionFieldType(Field collectionField); static Class<?> getMapKeyFieldType(Field mapField); static Class<?> getMapValueFieldType(Field mapField); static Class<?> getCollectionParameterType(MethodParameter methodParam); static Class<?> getMapKeyParameterType(MethodParameter methodParam); static Class<?> getMapValueParameterType(MethodParameter methodParam);  }### Answer:
@Test public void testGetMapKeyParameterType() throws Exception { final MethodParameter methodParameter = getConfigureMapMethodParameter(); final Class<?> mapValueParameterType = GenericCollectionTypeResolver.getMapKeyParameterType(methodParameter); assertEquals(String.class, mapValueParameterType); }