Boolean getLazyInit accessor indicating no explicit flag set

Closes gh-22694

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinition.java

@@ -145,7 +145,8 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 
 	private boolean abstractFlag = false;
 
-	private boolean lazyInit = false;
+	@Nullable
+	private Boolean lazyInit;
 
 	private int autowireMode = AUTOWIRE_NO;
 
@@ -229,7 +230,6 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 		setBeanClassName(original.getBeanClassName());
 		setScope(original.getScope());
 		setAbstract(original.isAbstract());
-		setLazyInit(original.isLazyInit());
 		setFactoryBeanName(original.getFactoryBeanName());
 		setFactoryMethodName(original.getFactoryMethodName());
 		setRole(original.getRole());
@@ -250,6 +250,10 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 			if (originalAbd.hasMethodOverrides()) {
 				setMethodOverrides(new MethodOverrides(originalAbd.getMethodOverrides()));
 			}
+			Boolean lazyInit = originalAbd.getLazyInit();
+			if (lazyInit != null) {
+				setLazyInit(lazyInit);
+			}
 			setAutowireMode(originalAbd.getAutowireMode());
 			setDependencyCheck(originalAbd.getDependencyCheck());
 			setDependsOn(originalAbd.getDependsOn());
@@ -269,6 +273,7 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 		else {
 			setConstructorArgumentValues(new ConstructorArgumentValues(original.getConstructorArgumentValues()));
 			setPropertyValues(new MutablePropertyValues(original.getPropertyValues()));
+			setLazyInit(original.isLazyInit());
 			setResourceDescription(original.getResourceDescription());
 		}
 	}
@@ -298,7 +303,6 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 			setScope(other.getScope());
 		}
 		setAbstract(other.isAbstract());
-		setLazyInit(other.isLazyInit());
 		if (StringUtils.hasLength(other.getFactoryBeanName())) {
 			setFactoryBeanName(other.getFactoryBeanName());
 		}
@@ -323,6 +327,10 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 			if (otherAbd.hasMethodOverrides()) {
 				getMethodOverrides().addOverrides(otherAbd.getMethodOverrides());
 			}
+			Boolean lazyInit = otherAbd.getLazyInit();
+			if (lazyInit != null) {
+				setLazyInit(lazyInit);
+			}
 			setAutowireMode(otherAbd.getAutowireMode());
 			setDependencyCheck(otherAbd.getDependencyCheck());
 			setDependsOn(otherAbd.getDependsOn());
@@ -346,16 +354,21 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 		else {
 			getConstructorArgumentValues().addArgumentValues(other.getConstructorArgumentValues());
 			getPropertyValues().addPropertyValues(other.getPropertyValues());
+			setLazyInit(other.isLazyInit());
 			setResourceDescription(other.getResourceDescription());
 		}
 	}
 
 	/**
 	 * Apply the provided default values to this bean.
-	 * @param defaults the defaults to apply
+	 * @param defaults the default settings to apply
+	 * @since 2.5
 	 */
 	public void applyDefaults(BeanDefinitionDefaults defaults) {
-		setLazyInit(defaults.isLazyInit());
+		Boolean lazyInit = defaults.getLazyInit();
+		if (lazyInit != null) {
+			setLazyInit(lazyInit);
+		}
 		setAutowireMode(defaults.getAutowireMode());
 		setDependencyCheck(defaults.getDependencyCheck());
 		setInitMethodName(defaults.getInitMethodName());
@@ -515,16 +528,29 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 	/**
 	 * Return whether this bean should be lazily initialized, i.e. not
 	 * eagerly instantiated on startup. Only applicable to a singleton bean.
+	 * @return whether to apply lazy-init semantics ({@code false} by default)
 	 */
 	@Override
 	public boolean isLazyInit() {
+		return (this.lazyInit != null && this.lazyInit.booleanValue());
+	}
+
+	/**
+	 * Return whether this bean should be lazily initialized, i.e. not
+	 * eagerly instantiated on startup. Only applicable to a singleton bean.
+	 * @return the lazy-init flag if explicitly set, or {@code null} otherwise
+	 * @since 5.2
+	 */
+	@Nullable
+	public Boolean getLazyInit() {
 		return this.lazyInit;
 	}
 
 	/**
 	 * Set the autowire mode. This determines whether any automagical detection
-	 * and setting of bean references will happen. Default is AUTOWIRE_NO,
-	 * which means there's no autowire.
+	 * and setting of bean references will happen. Default is AUTOWIRE_NO
+	 * which means there won't be convention-based autowiring by name or type
+	 * (however, there may still be explicit annotation-driven autowiring).
 	 * @param autowireMode the autowire mode to set.
 	 * Must be one of the constants defined in this class.
 	 * @see #AUTOWIRE_NO

spring-beans/src/main/java/org/springframework/beans/factory/support/BeanDefinitionDefaults.java

 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -23,16 +23,18 @@ import org.springframework.util.StringUtils;
  * A simple holder for {@code BeanDefinition} property defaults.
  *
  * @author Mark Fisher
+ * @author Juergen Hoeller
  * @since 2.5
  */
 public class BeanDefinitionDefaults {
 
-	private boolean lazyInit;
-
-	private int dependencyCheck = AbstractBeanDefinition.DEPENDENCY_CHECK_NONE;
+	@Nullable
+	private Boolean lazyInit;
 
 	private int autowireMode = AbstractBeanDefinition.AUTOWIRE_NO;
 
+	private int dependencyCheck = AbstractBeanDefinition.DEPENDENCY_CHECK_NONE;
+
 	@Nullable
 	private String initMethodName;
 
@@ -40,43 +42,95 @@ public class BeanDefinitionDefaults {
 	private String destroyMethodName;
 
 
+	/**
+	 * Set whether beans should be lazily initialized by default.
+	 * <p>If {@code false}, the bean will get instantiated on startup by bean
+	 * factories that perform eager initialization of singletons.
+	 */
 	public void setLazyInit(boolean lazyInit) {
 		this.lazyInit = lazyInit;
 	}
 
+	/**
+	 * Return whether beans should be lazily initialized by default, i.e. not
+	 * eagerly instantiated on startup. Only applicable to singleton beans.
+	 * @return whether to apply lazy-init semantics ({@code false} by default)
+	 */
 	public boolean isLazyInit() {
-		return this.lazyInit;
+		return (this.lazyInit != null && this.lazyInit.booleanValue());
 	}
 
-	public void setDependencyCheck(int dependencyCheck) {
-		this.dependencyCheck = dependencyCheck;
-	}
-
-	public int getDependencyCheck() {
-		return this.dependencyCheck;
+	/**
+	 * Return whether beans should be lazily initialized by default, i.e. not
+	 * eagerly instantiated on startup. Only applicable to singleton beans.
+	 * @return the lazy-init flag if explicitly set, or {@code null} otherwise
+	 * @since 5.2
+	 */
+	@Nullable
+	public Boolean getLazyInit() {
+		return this.lazyInit;
 	}
 
+	/**
+	 * Set the autowire mode. This determines whether any automagical detection
+	 * and setting of bean references will happen. Default is AUTOWIRE_NO
+	 * which means there won't be convention-based autowiring by name or type
+	 * (however, there may still be explicit annotation-driven autowiring).
+	 * @param autowireMode the autowire mode to set.
+	 * Must be one of the constants defined in {@link AbstractBeanDefinition}.
+	 */
 	public void setAutowireMode(int autowireMode) {
 		this.autowireMode = autowireMode;
 	}
 
+	/**
+	 * Return the default autowire mode.
+	 */
 	public int getAutowireMode() {
 		return this.autowireMode;
 	}
 
+	/**
+	 * Set the dependency check code.
+	 * @param dependencyCheck the code to set.
+	 * Must be one of the constants defined in {@link AbstractBeanDefinition}.
+	 */
+	public void setDependencyCheck(int dependencyCheck) {
+		this.dependencyCheck = dependencyCheck;
+	}
+
+	/**
+	 * Return the default dependency check code.
+	 */
+	public int getDependencyCheck() {
+		return this.dependencyCheck;
+	}
+
+	/**
+	 * Set the name of the default initializer method.
+	 */
 	public void setInitMethodName(@Nullable String initMethodName) {
 		this.initMethodName = (StringUtils.hasText(initMethodName) ? initMethodName : null);
 	}
 
+	/**
+	 * Return the name of the default initializer method.
+	 */
 	@Nullable
 	public String getInitMethodName() {
 		return this.initMethodName;
 	}
 
+	/**
+	 * Set the name of the default destroy method.
+	 */
 	public void setDestroyMethodName(@Nullable String destroyMethodName) {
 		this.destroyMethodName = (StringUtils.hasText(destroyMethodName) ? destroyMethodName : null);
 	}
 
+	/**
+	 * Return the name of the default destroy method.
+	 */
 	@Nullable
 	public String getDestroyMethodName() {
 		return this.destroyMethodName;

spring-beans/src/test/java/org/springframework/beans/factory/DefaultListableBeanFactoryTests.java

@@ -2353,6 +2353,27 @@ public class DefaultListableBeanFactoryTests {
 		lbf.preInstantiateSingletons();
 	}
 
+	@Test
+	public void testLazyInitFlag() {
+		DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
+		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);
+		bd1.setLazyInit(true);
+		factory.registerBeanDefinition("tb1", bd1);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setLazyInit(false);
+		factory.registerBeanDefinition("tb2", bd2);
+		factory.registerBeanDefinition("tb3", new RootBeanDefinition(TestBean.class));
+
+		assertEquals(Boolean.TRUE, ((AbstractBeanDefinition) factory.getMergedBeanDefinition("tb1")).getLazyInit());
+		assertEquals(Boolean.FALSE, ((AbstractBeanDefinition) factory.getMergedBeanDefinition("tb2")).getLazyInit());
+		assertNull(((AbstractBeanDefinition) factory.getMergedBeanDefinition("tb3")).getLazyInit());
+
+		factory.preInstantiateSingletons();
+		assertFalse(factory.containsSingleton("tb1"));
+		assertTrue(factory.containsSingleton("tb2"));
+		assertTrue(factory.containsSingleton("tb3"));
+	}
+
 	@Test
 	public void testLazyInitFactory() {
 		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
@@ -2877,8 +2898,8 @@ public class DefaultListableBeanFactoryTests {
 		}
 	}
 
-	@SuppressWarnings("unchecked")
 	@Test
+	@SuppressWarnings("unchecked")
 	public void testInitSecurityAwarePrototypeBean() {
 		final DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
 		RootBeanDefinition bd = new RootBeanDefinition(TestSecuredBean.class);
@@ -2889,12 +2910,7 @@ public class DefaultListableBeanFactoryTests {
 		subject.getPrincipals().add(new TestPrincipal("user1"));
 
 		TestSecuredBean bean = (TestSecuredBean) Subject.doAsPrivileged(subject,
-				new PrivilegedAction() {
-					@Override
-					public Object run() {
-						return lbf.getBean("test");
-					}
-				}, null);
+				(PrivilegedAction) () -> lbf.getBean("test"), null);
 		assertNotNull(bean);
 		assertEquals("user1", bean.getUserName());
 	}