diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/DefaultExceptionTranslatorExecuteListener.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/DefaultExceptionTranslatorExecuteListener.java
index 504307a34ed..2866d63d67d 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/DefaultExceptionTranslatorExecuteListener.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/DefaultExceptionTranslatorExecuteListener.java
@@ -23,6 +23,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.jooq.ExecuteContext;
 import org.jooq.SQLDialect;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator;
@@ -117,7 +118,7 @@ final class DefaultExceptionTranslatorExecuteListener implements ExceptionTransl
 					: new SQLExceptionSubclassTranslator();
 		}
 
-		private String getSpringDbName(SQLDialect dialect) {
+		private @Nullable String getSpringDbName(@Nullable SQLDialect dialect) {
 			return (dialect != null && dialect.thirdParty() != null) ? dialect.thirdParty().springDbName() : null;
 		}
 
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqAutoConfiguration.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqAutoConfiguration.java
index 706e282e691..304d0aaad88 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqAutoConfiguration.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqAutoConfiguration.java
@@ -133,6 +133,7 @@ public final class JooqAutoConfiguration {
 			throw new JaxbNotAvailableException();
 		}
 		Resource resource = properties.getConfig();
+		Assert.state(resource != null, "'resource' must not be null");
 		Assert.state(resource.exists(),
 				() -> "Resource %s set in spring.jooq.config does not exist".formatted(resource));
 		try (InputStream stream = resource.getInputStream()) {
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqProperties.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqProperties.java
index 387736785e7..dfceeb8ce9e 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqProperties.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/JooqProperties.java
@@ -19,6 +19,7 @@ package org.springframework.boot.jooq.autoconfigure;
 import javax.sql.DataSource;
 
 import org.jooq.SQLDialect;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.core.io.Resource;
@@ -37,26 +38,26 @@ public class JooqProperties {
 	/**
 	 * SQL dialect to use. Auto-detected by default.
 	 */
-	private SQLDialect sqlDialect;
+	private @Nullable SQLDialect sqlDialect;
 
 	/**
 	 * Location of the jOOQ config file.
 	 */
-	private Resource config;
+	private @Nullable Resource config;
 
-	public SQLDialect getSqlDialect() {
+	public @Nullable SQLDialect getSqlDialect() {
 		return this.sqlDialect;
 	}
 
-	public void setSqlDialect(SQLDialect sqlDialect) {
+	public void setSqlDialect(@Nullable SQLDialect sqlDialect) {
 		this.sqlDialect = sqlDialect;
 	}
 
-	public Resource getConfig() {
+	public @Nullable Resource getConfig() {
 		return this.config;
 	}
 
-	public void setConfig(Resource config) {
+	public void setConfig(@Nullable Resource config) {
 		this.config = config;
 	}
 
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/NoDslContextBeanFailureAnalyzer.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/NoDslContextBeanFailureAnalyzer.java
index 10c88c3c92e..f3e85662554 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/NoDslContextBeanFailureAnalyzer.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/NoDslContextBeanFailureAnalyzer.java
@@ -17,6 +17,7 @@
 package org.springframework.boot.jooq.autoconfigure;
 
 import org.jooq.DSLContext;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
@@ -35,7 +36,7 @@ class NoDslContextBeanFailureAnalyzer extends AbstractFailureAnalyzer<NoSuchBean
 	}
 
 	@Override
-	protected FailureAnalysis analyze(Throwable rootFailure, NoSuchBeanDefinitionException cause) {
+	protected @Nullable FailureAnalysis analyze(Throwable rootFailure, NoSuchBeanDefinitionException cause) {
 		if (DSLContext.class.equals(cause.getBeanType()) && hasR2dbcAutoConfiguration()) {
 			return new FailureAnalysis(
 					"jOOQ has not been auto-configured as R2DBC has been auto-configured in favor of JDBC and jOOQ "
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SpringTransactionProvider.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SpringTransactionProvider.java
index 2792af85069..526338a6726 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SpringTransactionProvider.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SpringTransactionProvider.java
@@ -23,6 +23,7 @@ import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionStatus;
 import org.springframework.transaction.support.DefaultTransactionDefinition;
+import org.springframework.util.Assert;
 
 /**
  * Allows Spring Transaction to be used with jOOQ.
@@ -61,6 +62,7 @@ public class SpringTransactionProvider implements TransactionProvider {
 
 	private TransactionStatus getTransactionStatus(TransactionContext ctx) {
 		SpringTransaction transaction = (SpringTransaction) ctx.transaction();
+		Assert.state(transaction != null, "'transaction' must not be null");
 		return transaction.getTxStatus();
 	}
 
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SqlDialectLookup.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SqlDialectLookup.java
index 4d524acf7bb..44da897d590 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SqlDialectLookup.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/SqlDialectLookup.java
@@ -25,6 +25,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.jooq.SQLDialect;
 import org.jooq.tools.jdbc.JDBCUtils;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Utility to lookup well known {@link SQLDialect SQLDialects} from a {@link DataSource}.
@@ -45,7 +46,7 @@ final class SqlDialectLookup {
 	 * @param dataSource the source {@link DataSource}
 	 * @return the most suitable {@link SQLDialect}
 	 */
-	static SQLDialect getDialect(DataSource dataSource) {
+	static SQLDialect getDialect(@Nullable DataSource dataSource) {
 		try (Connection connection = (dataSource != null) ? dataSource.getConnection() : null) {
 			return JDBCUtils.dialect(connection);
 		}
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/package-info.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/package-info.java
index caf069ee1c2..7ba60da1156 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/package-info.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/autoconfigure/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Auto-configuration for jOOQ.
  */
+@NullMarked
 package org.springframework.boot.jooq.autoconfigure;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/package-info.java b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/package-info.java
index 49b742b81cd..9db616a25f0 100644
--- a/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/package-info.java
+++ b/module/spring-boot-jooq/src/main/java/org/springframework/boot/jooq/package-info.java
@@ -19,4 +19,7 @@
  *
  * @see org.springframework.boot.json.JsonParser
  */
+@NullMarked
 package org.springframework.boot.jooq;
+
+import org.jspecify.annotations.NullMarked;