Consider @Import classes as lite @Configuration

Allow classes that are annotated with @Import to be considered as 'lite'
@Configuration candidates. Allows the AnnotationConfigApplicationContext
to directly register @Import beans even if they are not @Components.

Issue: SPR-10533

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassUtils.java

@@ -101,9 +101,12 @@ abstract class ConfigurationClassUtils {
 	}
 
 	public static boolean isLiteConfigurationCandidate(AnnotationMetadata metadata) {
-		return !metadata.isInterface() && // not an interface or an annotation
+		if(metadata.isInterface()) {
-				(metadata.isAnnotated(Component.class.getName()) ||
+			return false; // do not consider an interface or an annotation
-				metadata.hasAnnotatedMethods(Bean.class.getName()));
+		}
+		return metadata.isAnnotated(Import.class.getName()) ||
+				metadata.isAnnotated(Component.class.getName()) ||
+				metadata.hasAnnotatedMethods(Bean.class.getName());
 	}
 
 

spring-context/src/test/java/org/springframework/context/annotation/configuration/ImportAnnotationDetectionTests.java

@@ -25,12 +25,15 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import org.junit.Test;
+import org.springframework.stereotype.Service;
 import org.springframework.tests.sample.beans.TestBean;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 
+import static org.junit.Assert.*;
+
 /**
  * Tests that @Import may be used both as a locally declared and meta-declared
  * annotation, that all declarations are processed, and that any local declaration
@@ -70,6 +73,16 @@ public class ImportAnnotationDetectionTests {
 		assertThat(ctx.getBean("testBean2", TestBean.class).getName(), is("2a"));
 	}
 
+	@Test
+	public void importFromBean() throws Exception {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(ImportFromBean.class);
+		ctx.refresh();
+		assertThat(ctx.containsBean("importAnnotationDetectionTests.ImportFromBean"), is(true));
+		assertThat(ctx.containsBean("testBean1"), is(true));
+		assertThat(ctx.getBean("testBean1", TestBean.class).getName(), is("1"));
+	}
+
 	@Configuration
 	@MetaImport1
 	@MetaImport2
@@ -136,4 +149,9 @@ public class ImportAnnotationDetectionTests {
 			return new TestBean("3");
 		}
 	}
+
+	@MetaImport1
+	static class ImportFromBean {
+
+	}
 }