### Question:
ReflectionUtils { public <A extends Annotation> A getParameterAnnotation(final Parameter parameter, final Class<A> annotationClazz, final String declaringClassName) { final String cacheKey = "ParameterAnnotation-" + declaringClassName + "-" + parameter.getName() + "-" + annotationClazz.getName(); return getAnnotation(parameter, annotationClazz, cacheKey); }  Object invokeMethod(final Method method, final Object target, final Object... args); boolean isSetter(final Method method); boolean isGetter(final Method method); Object getFieldValue(final Object target, final Field field); @SuppressWarnings("unchecked") Object getFieldValue(final Object target, final String fieldName, final Class<?> fieldType); A getFieldAnnotation(final Field field, final Class<A> annotationClazz); A getParameterAnnotation(final Parameter parameter, final Class<A> annotationClazz, final String declaringClassName); Field getDeclaredField(final String fieldName, final Class<?> targetClass); Class<?> getDeclaredFieldType(final String fieldName, final Class<?> clazz); void setFieldValue(final Object target, final String fieldName, final Object fieldValue); void setFieldValue(final Object target, final Field field, final Object fieldValue); Method getSetterMethodForField(final Class<?> fieldClass, final String fieldName, final Class<?> fieldType); Class<?> getGenericFieldType(final Field field); MapType getMapGenericType(final Type fieldType, final String declaringClass, final String fieldName); Class<?> getArgumentTypeClass(final Object argument, final String declaringClass, final String fieldName, final boolean getNestedGenericClass); Class<?> getArrayType(final Field arrayField);  }### Answer:
@Test public void testGetParameterAnnotationReturnsNullIfTheAnnotationDoesNotExists() { Parameter parameter = mock(Parameter.class); when(parameter.isAnnotationPresent(NotNull.class)).thenReturn(false); final Annotation actual = underTest.getParameterAnnotation(parameter, NotNull.class, DECLARING_CLASS_NAME); assertThat(actual).isNull(); }