### Question:
BeanConstraintValidatorFactory implements ConstraintValidatorFactory { @Override public void releaseInstance(ConstraintValidator <?, ?> instance) { String beanName = getBeanName(instance.getClass()); beanFactory.destroyBean(beanName, instance); } BeanConstraintValidatorFactory(ConfigurableListableBeanFactory beanFactory); @Override T getInstance(Class<T> key); @Override void releaseInstance(ConstraintValidator <?, ?> instance);  }### Answer:
@Test public void testReleaseInstance() { String[] names = {validatorBeanName}; when(beanFactory.getBeanNamesForType(validator.getClass())).thenReturn(names); factory.releaseInstance(validator); verify(beanFactory).destroyBean(validatorBeanName, validator); }