AnnotatedBeanDefinitionReader should respect @Fallback qualifier analogous to @Primary

Also add tests to cover qualifier classes.

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

@@ -43,6 +43,7 @@ import org.springframework.util.Assert;
  * @author Chris Beams
  * @author Sam Brannen
  * @author Phillip Webb
+ * @author Yanming Zhou
  * @since 3.0
  * @see AnnotationConfigApplicationContext#register
  */
@@ -266,6 +267,9 @@ public class AnnotatedBeanDefinitionReader {
 				if (Primary.class == qualifier) {
 					abd.setPrimary(true);
 				}
+				else if (Fallback.class == qualifier) {
+					abd.setFallback(true);
+				}
 				else if (Lazy.class == qualifier) {
 					abd.setLazyInit(true);
 				}

spring-context/src/test/java/org/springframework/context/annotation/AnnotatedBeanDefinitionReaderTests.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.context.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.context.support.GenericApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Yanming Zhou
+ */
+class AnnotatedBeanDefinitionReaderTests {
+
+	@Test
+	void registerBeanWithQualifiers() {
+		GenericApplicationContext context = new GenericApplicationContext();
+		AnnotatedBeanDefinitionReader reader = new AnnotatedBeanDefinitionReader(context);
+
+		reader.registerBean(TestBean.class, "primary", Primary.class);
+		assertThat(context.getBeanDefinition("primary").isPrimary()).isTrue();
+
+		reader.registerBean(TestBean.class, "fallback", Fallback.class);
+		assertThat(context.getBeanDefinition("fallback").isFallback()).isTrue();
+
+		reader.registerBean(TestBean.class, "lazy", Lazy.class);
+		assertThat(context.getBeanDefinition("lazy").isLazyInit()).isTrue();
+
+		reader.registerBean(TestBean.class, "customQualifier", CustomQualifier.class);
+		assertThat(context.getBeanDefinition("customQualifier"))
+				.isInstanceOfSatisfying(AbstractBeanDefinition.class, abd ->
+					assertThat(abd.hasQualifier(CustomQualifier.class.getTypeName())).isTrue());
+	}
+
+	@Lazy(false)
+	static class TestBean {
+
+	}
+
+	@Target({ElementType.TYPE, ElementType.METHOD})
+	@Retention(RetentionPolicy.RUNTIME)
+	@Qualifier
+	@interface CustomQualifier {
+
+	}
+}