@Lazy annotation (#3809)

spring-core/src/main/java/com/baeldung/lazy/AppConfig.java

@@ -0,0 +1,23 @@
+package com.baeldung.lazy;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Lazy;
+
+@Lazy
+@Configuration
+@ComponentScan(basePackages = "com.baeldung.lazy")
+public class AppConfig {
+
+    @Lazy
+    @Bean
+    public Region getRegion(){
+        return new Region();
+    }
+
+    @Bean
+    public Country getCountry(){
+        return new Country();
+    }
+}

spring-core/src/main/java/com/baeldung/lazy/City.java

@@ -0,0 +1,13 @@
+package com.baeldung.lazy;
+
+import org.springframework.context.annotation.Lazy;
+import org.springframework.stereotype.Component;
+
+@Lazy
+@Component
+public class City {
+
+    public City() {
+        System.out.println("City bean initialized");
+    }
+}

spring-core/src/main/java/com/baeldung/lazy/Country.java

@@ -0,0 +1,8 @@
+package com.baeldung.lazy;
+
+public class Country {
+
+    public Country() {
+        System.out.println("Country bean initialized");
+    }
+}

spring-core/src/main/java/com/baeldung/lazy/Region.java

@@ -0,0 +1,19 @@
+package com.baeldung.lazy;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Lazy;
+
+public class Region {
+
+    @Lazy
+    @Autowired
+    private City city;
+
+    public Region() {
+        System.out.println("Region bean initialized");
+    }
+
+    public City getCityInstance() {
+        return city;
+    }
+}

spring-core/src/test/java/com/baeldung/Lazy/LazyAnnotationUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.Lazy;
+
+import com.baeldung.lazy.AppConfig;
+import com.baeldung.lazy.Country;
+import com.baeldung.lazy.Region;
+import org.junit.Test;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+
+public class LazyAnnotationUnitTest {
+
+    @Test
+    public void givenLazyAnnotation_whenConfigClass_thenLazyAll() {
+        // Add @Lazy to AppConfig.class while testing
+        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+        ctx.register(AppConfig.class);
+        ctx.refresh();
+        ctx.getBean(Region.class);
+        ctx.getBean(Country.class);
+    }
+
+    @Test
+    public void givenLazyAnnotation_whenAutowire_thenLazyBean() {
+        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+        ctx.register(AppConfig.class);
+        ctx.refresh();
+        Region region = ctx.getBean(Region.class);
+        region.getCityInstance();
+    }
+
+    @Test
+    public void givenLazyAnnotation_whenBeanConfig_thenLazyBean() {
+        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+        ctx.register(AppConfig.class);
+        ctx.refresh();
+        ctx.getBean(Region.class);
+    }
+}