Doc: Lazy context is not validated on creation [SPR-11495]

[spring-projects-issues]

Maarten Winkels opened SPR-11495 and commented

The spring documentation states:

The Spring container validates the configuration of each bean as the container is created, including the validation of whether bean reference properties refer to valid beans. However, the bean properties themselves are not set until the bean is actually created. Beans that are singleton-scoped and set to be pre-instantiated (the default) are created when the container is created.

But a simple tests shows that a missing bean is not detected in a lazy context until it is created.

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Affects: 3.2.6, 3.2.8, 4.0.2

Issue Links:

• @ComponentScan does not allow for registering beans with lazy initialization [SPR-10459] #15092 @ComponentScan does not allow for registering beans with lazy initialization

[spring-projects-issues]

Maarten Winkels commented

The test below should fail, since the bean in the context references a bean that is not defined. However, the test succeeds. Removing the Lazy-annotation makes the test fail as expected.

import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.*;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.*;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@ContextConfiguration
@RunWith(SpringJUnit4ClassRunner.class)
public class ContextValidationTest
{

	@Configuration
	@Lazy
	public static class Config {
		
		@Bean
		@Autowired
		public String lowerCaseName(@Qualifier("MyName") String name) {
			return name.toLowerCase();
		}
		
	}
	
	@Autowired
	private ApplicationContext applicationContext;

	@Test
	public void shouldInitializeContext() {
		assertThat(applicationContext, is(notNullValue()));
	}
}

[spring-projects-issues]

Juergen Hoeller commented

I'm afraid this is a rather fundamental consequence of annotation-driven autowiring, where the actual demand for type-matching target beans can't easily be validated upfront.

That said, we at least need to update the documentation there: That statement is only valid for externally specified bean references by name. From a modern-day perspective, I'd rather drop that entire validation claim.

Juergen