rojoangel / spring-initialization

Spring initialization PoC

Spring initialization

The aim of this PoC is to better understand the order in which things gets initialized in a spring boot application. The application has

• a InitializationApplication SpringBootApplication
• a RuntimeBean Component
• a InitializationApplicationTests SpringBootTest
• a TestBean Bean declared in the TestConfiguration

Run the tests by executing

mvn test 

Outcome

By checking the logs we can see that the initialization order is as follows:

Run tests

Test class

• initialization methods
• @BeforeAll method
• constructor

spring application config loading

Runtime component

• static initialization methods
• constructor
• @PostConstruct method

spring test config loading

Test component

• static initialization methods
• constructor
• @PostConstruct method

test execution

Test class

• @PostConstruct method
• @BeforeEach method
• @AfterEach method

if @DirtiesContext & spring context needs reloading

(Note that no static methods are called during context reloading)

Runtime component

• constructor
• @PostConstruct method

Test component

• constructor
• @PostConstruct method

Test class

• @PostConstruct method
• @BeforeEach method
• @AfterEach method