diff --git a/config/checkstyle/checkstyle-suppressions.xml b/config/checkstyle/checkstyle-suppressions.xml
index d869769c17a..66d71260f6a 100644
--- a/config/checkstyle/checkstyle-suppressions.xml
+++ b/config/checkstyle/checkstyle-suppressions.xml
@@ -91,4 +91,5 @@
 	<suppress files="Bindable\.java" checks="NoWhitespaceBefore" message="'...' is preceded with whitespace"/>
 	<suppress files="LambdaSafe\.java" checks="NoWhitespaceBefore" message="'...' is preceded with whitespace"/>
 	<suppress files="ConditionMessage\.java" checks="NoWhitespaceBefore" message="'...' is preceded with whitespace"/>
+	<suppress files="EntityManagerFactoryBuilder\.java" checks="NoWhitespaceBefore" message="'...' is preceded with whitespace"/>
 </suppressions>
diff --git a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/EntityManagerFactoryBuilder.java b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/EntityManagerFactoryBuilder.java
index 1cffb77e427..9f32da75362 100644
--- a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/EntityManagerFactoryBuilder.java
+++ b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/EntityManagerFactoryBuilder.java
@@ -26,6 +26,8 @@ import java.util.function.Function;
 
 import javax.sql.DataSource;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.orm.jpa.JpaVendorAdapter;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
@@ -53,15 +55,15 @@ public class EntityManagerFactoryBuilder {
 
 	private final JpaVendorAdapter jpaVendorAdapter;
 
-	private final PersistenceUnitManager persistenceUnitManager;
+	private final @Nullable PersistenceUnitManager persistenceUnitManager;
 
 	private final Function<DataSource, Map<String, ?>> jpaPropertiesFactory;
 
-	private final URL persistenceUnitRootLocation;
+	private final @Nullable URL persistenceUnitRootLocation;
 
-	private AsyncTaskExecutor bootstrapExecutor;
+	private @Nullable AsyncTaskExecutor bootstrapExecutor;
 
-	private PersistenceUnitPostProcessor[] persistenceUnitPostProcessors;
+	private PersistenceUnitPostProcessor @Nullable [] persistenceUnitPostProcessors;
 
 	/**
 	 * Create a new instance passing in the common pieces that will be shared if multiple
@@ -74,7 +76,8 @@ public class EntityManagerFactoryBuilder {
 	 * @since 3.4.4
 	 */
 	public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,
-			Function<DataSource, Map<String, ?>> jpaPropertiesFactory, PersistenceUnitManager persistenceUnitManager) {
+			Function<DataSource, Map<String, ?>> jpaPropertiesFactory,
+			@Nullable PersistenceUnitManager persistenceUnitManager) {
 		this(jpaVendorAdapter, jpaPropertiesFactory, persistenceUnitManager, null);
 	}
 
@@ -91,8 +94,8 @@ public class EntityManagerFactoryBuilder {
 	 * @since 3.4.4
 	 */
 	public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,
-			Function<DataSource, Map<String, ?>> jpaPropertiesFactory, PersistenceUnitManager persistenceUnitManager,
-			URL persistenceUnitRootLocation) {
+			Function<DataSource, Map<String, ?>> jpaPropertiesFactory,
+			@Nullable PersistenceUnitManager persistenceUnitManager, @Nullable URL persistenceUnitRootLocation) {
 		this.jpaVendorAdapter = jpaVendorAdapter;
 		this.persistenceUnitManager = persistenceUnitManager;
 		this.jpaPropertiesFactory = jpaPropertiesFactory;
@@ -137,15 +140,15 @@ public class EntityManagerFactoryBuilder {
 
 		private final DataSource dataSource;
 
-		private PersistenceManagedTypes managedTypes;
+		private @Nullable PersistenceManagedTypes managedTypes;
 
-		private String[] packagesToScan;
+		private String @Nullable [] packagesToScan;
 
-		private String persistenceUnit;
+		private @Nullable String persistenceUnit;
 
 		private final Map<String, Object> properties = new HashMap<>();
 
-		private String[] mappingResources;
+		private String @Nullable [] mappingResources;
 
 		private boolean jta;
 
@@ -159,7 +162,7 @@ public class EntityManagerFactoryBuilder {
 		 * @param managedTypes managed types.
 		 * @return the builder for fluent usage
 		 */
-		public Builder managedTypes(PersistenceManagedTypes managedTypes) {
+		public Builder managedTypes(@Nullable PersistenceManagedTypes managedTypes) {
 			this.managedTypes = managedTypes;
 			return this;
 		}
@@ -170,7 +173,7 @@ public class EntityManagerFactoryBuilder {
 		 * @return the builder for fluent usage
 		 * @see #managedTypes(PersistenceManagedTypes)
 		 */
-		public Builder packages(String... packagesToScan) {
+		public Builder packages(String @Nullable ... packagesToScan) {
 			this.packagesToScan = packagesToScan;
 			return this;
 		}
@@ -197,7 +200,7 @@ public class EntityManagerFactoryBuilder {
 		 * @param persistenceUnit the name of the persistence unit
 		 * @return the builder for fluent usage
 		 */
-		public Builder persistenceUnit(String persistenceUnit) {
+		public Builder persistenceUnit(@Nullable String persistenceUnit) {
 			this.persistenceUnit = persistenceUnit;
 			return this;
 		}
@@ -223,7 +226,7 @@ public class EntityManagerFactoryBuilder {
 		 * @param mappingResources the mapping resources to use
 		 * @return the builder for fluent usage
 		 */
-		public Builder mappingResources(String... mappingResources) {
+		public Builder mappingResources(String @Nullable ... mappingResources) {
 			this.mappingResources = mappingResources;
 			return this;
 		}
@@ -264,7 +267,7 @@ public class EntityManagerFactoryBuilder {
 				entityManagerFactoryBean.setManagedTypes(this.managedTypes);
 			}
 			else {
-				entityManagerFactoryBean.setPackagesToScan(this.packagesToScan);
+				setPackagesToScan(entityManagerFactoryBean);
 			}
 			Map<String, ?> jpaProperties = EntityManagerFactoryBuilder.this.jpaPropertiesFactory.apply(this.dataSource);
 			entityManagerFactoryBean.getJpaPropertyMap().putAll(new LinkedHashMap<>(jpaProperties));
@@ -286,6 +289,14 @@ public class EntityManagerFactoryBuilder {
 			return entityManagerFactoryBean;
 		}
 
+		// TODO: Review this. The test
+		// HibernateJpaAutoConfigurationTests.usesManuallyDefinedLocalContainerEntityManagerFactoryBeanUsingBuilder
+		// fails if an non-null assert is added
+		@SuppressWarnings("NullAway")
+		private void setPackagesToScan(LocalContainerEntityManagerFactoryBean entityManagerFactoryBean) {
+			entityManagerFactoryBean.setPackagesToScan(this.packagesToScan);
+		}
+
 	}
 
 }
diff --git a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaBaseConfiguration.java b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaBaseConfiguration.java
index 428c2f1f958..de2cbe802bf 100644
--- a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaBaseConfiguration.java
+++ b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaBaseConfiguration.java
@@ -25,6 +25,7 @@ import javax.sql.DataSource;
 import jakarta.persistence.EntityManagerFactory;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.ObjectProvider;
@@ -82,7 +83,7 @@ public abstract class JpaBaseConfiguration {
 
 	private final JpaProperties properties;
 
-	private final JtaTransactionManager jtaTransactionManager;
+	private final @Nullable JtaTransactionManager jtaTransactionManager;
 
 	protected JpaBaseConfiguration(DataSource dataSource, JpaProperties properties,
 			ObjectProvider<JtaTransactionManager> jtaTransactionManager) {
@@ -163,7 +164,7 @@ public abstract class JpaBaseConfiguration {
 	protected void customizeVendorProperties(Map<String, Object> vendorProperties) {
 	}
 
-	private String[] getMappingResources() {
+	private String @Nullable [] getMappingResources() {
 		List<String> mappingResources = this.properties.getMappingResources();
 		return (!ObjectUtils.isEmpty(mappingResources) ? StringUtils.toStringArray(mappingResources) : null);
 	}
@@ -172,7 +173,7 @@ public abstract class JpaBaseConfiguration {
 	 * Return the JTA transaction manager.
 	 * @return the transaction manager or {@code null}
 	 */
-	protected JtaTransactionManager getJtaTransactionManager() {
+	protected @Nullable JtaTransactionManager getJtaTransactionManager() {
 		return this.jtaTransactionManager;
 	}
 
diff --git a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaProperties.java b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaProperties.java
index 77bb0d5737e..4d9f151e666 100644
--- a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaProperties.java
+++ b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/JpaProperties.java
@@ -21,6 +21,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.orm.jpa.vendor.Database;
 
@@ -51,13 +53,13 @@ public class JpaProperties {
 	 * Name of the target database to operate on, auto-detected by default. Can be
 	 * alternatively set using the "Database" enum.
 	 */
-	private String databasePlatform;
+	private @Nullable String databasePlatform;
 
 	/**
 	 * Target database to operate on, auto-detected by default. Can be alternatively set
 	 * using the "databasePlatform" property.
 	 */
-	private Database database;
+	private @Nullable Database database;
 
 	/**
 	 * Whether to initialize the schema on startup.
@@ -73,7 +75,7 @@ public class JpaProperties {
 	 * Register OpenEntityManagerInViewInterceptor. Binds a JPA EntityManager to the
 	 * thread for the entire processing of the request.
 	 */
-	private Boolean openInView;
+	private @Nullable Boolean openInView;
 
 	public Map<String, String> getProperties() {
 		return this.properties;
@@ -87,19 +89,19 @@ public class JpaProperties {
 		return this.mappingResources;
 	}
 
-	public String getDatabasePlatform() {
+	public @Nullable String getDatabasePlatform() {
 		return this.databasePlatform;
 	}
 
-	public void setDatabasePlatform(String databasePlatform) {
+	public void setDatabasePlatform(@Nullable String databasePlatform) {
 		this.databasePlatform = databasePlatform;
 	}
 
-	public Database getDatabase() {
+	public @Nullable Database getDatabase() {
 		return this.database;
 	}
 
-	public void setDatabase(Database database) {
+	public void setDatabase(@Nullable Database database) {
 		this.database = database;
 	}
 
@@ -119,11 +121,11 @@ public class JpaProperties {
 		this.showSql = showSql;
 	}
 
-	public Boolean getOpenInView() {
+	public @Nullable Boolean getOpenInView() {
 		return this.openInView;
 	}
 
-	public void setOpenInView(Boolean openInView) {
+	public void setOpenInView(@Nullable Boolean openInView) {
 		this.openInView = openInView;
 	}
 
diff --git a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/package-info.java b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/package-info.java
index f336351258d..b999cec18c8 100644
--- a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/package-info.java
+++ b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/autoconfigure/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Base Auto-configuration for JPA and Spring ORM.
  */
+@NullMarked
 package org.springframework.boot.jpa.autoconfigure;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/package-info.java b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/package-info.java
index eb455d693a8..325ebaff4d8 100644
--- a/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/package-info.java
+++ b/module/spring-boot-jpa/src/main/java/org/springframework/boot/jpa/package-info.java
@@ -17,4 +17,7 @@
 /**
  * JPA Support classes.
  */
+@NullMarked
 package org.springframework.boot.jpa;
+
+import org.jspecify.annotations.NullMarked;