diff --git a/.mvn/jvm.config b/.mvn/jvm.config
new file mode 100644
index 0000000..32599ce
--- /dev/null
+++ b/.mvn/jvm.config
@@ -0,0 +1,10 @@
+--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED
diff --git a/core/src/main/java/org/springframework/plugin/core/config/PluginRegistriesBeanDefinitionRegistrar.java b/core/src/main/java/org/springframework/plugin/core/config/PluginRegistriesBeanDefinitionRegistrar.java
index 43e3741..2876549 100644
--- a/core/src/main/java/org/springframework/plugin/core/config/PluginRegistriesBeanDefinitionRegistrar.java
+++ b/core/src/main/java/org/springframework/plugin/core/config/PluginRegistriesBeanDefinitionRegistrar.java
@@ -17,6 +17,7 @@ package org.springframework.plugin.core.config;
 
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Qualifier;
@@ -58,8 +59,13 @@ public class PluginRegistriesBeanDefinitionRegistrar implements ImportBeanDefini
 			return;
 		}
 
+		@Nullable
 		Class<?>[] types = (Class<?>[]) annotationAttributes.get("value");
 
+		if (types == null) {
+			return;
+		}
+
 		for (Class<?> type : types) {
 
 			RootBeanDefinition beanDefinition = new RootBeanDefinition(PluginRegistryFactoryBean.class);
diff --git a/core/src/main/java/org/springframework/plugin/core/config/package-info.java b/core/src/main/java/org/springframework/plugin/core/config/package-info.java
index 4d50322..867f261 100644
--- a/core/src/main/java/org/springframework/plugin/core/config/package-info.java
+++ b/core/src/main/java/org/springframework/plugin/core/config/package-info.java
@@ -1,5 +1,5 @@
 /**
  * This package contains configuration support classes to ease registry configuration with Spring namespaces.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.plugin.core.config;
-
diff --git a/core/src/main/java/org/springframework/plugin/core/package-info.java b/core/src/main/java/org/springframework/plugin/core/package-info.java
index 4aa38c0..8b5fadb 100644
--- a/core/src/main/java/org/springframework/plugin/core/package-info.java
+++ b/core/src/main/java/org/springframework/plugin/core/package-info.java
@@ -2,5 +2,5 @@
  * This package contains the core plugin API. It allows other modules implementing components that extend functionality
  * defined by a plugin interface. Plugin clients can be equipped with plugin implementations.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.plugin.core;
diff --git a/core/src/main/java/org/springframework/plugin/core/support/PluginRegistryFactoryBean.java b/core/src/main/java/org/springframework/plugin/core/support/PluginRegistryFactoryBean.java
index fcdd934..7cbacb5 100644
--- a/core/src/main/java/org/springframework/plugin/core/support/PluginRegistryFactoryBean.java
+++ b/core/src/main/java/org/springframework/plugin/core/support/PluginRegistryFactoryBean.java
@@ -22,6 +22,8 @@ import java.util.List;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import org.jspecify.annotations.NonNull;
+import org.jspecify.annotations.Nullable;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
@@ -30,8 +32,6 @@ import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
-import org.springframework.lang.NonNull;
-import org.springframework.lang.Nullable;
 import org.springframework.plugin.core.OrderAwarePluginRegistry;
 import org.springframework.plugin.core.Plugin;
 import org.springframework.plugin.core.PluginRegistry;
@@ -46,7 +46,7 @@ public class PluginRegistryFactoryBean<T extends Plugin<S>, S>
 
 	private Collection<Class<?>> exclusions = Collections.emptySet();
 	private @Nullable Class<T> type;
-	private ListableBeanFactory factory;
+	private @Nullable ListableBeanFactory factory;
 
 	/**
 	 * Configures the type of beans to be looked up.
@@ -103,6 +103,12 @@ public class PluginRegistryFactoryBean<T extends Plugin<S>, S>
 			throw new IllegalStateException("No plugin type configured!");
 		}
 
+		var factory = this.factory;
+
+		if (factory == null) {
+			throw new IllegalStateException("No ListableBeanFactory configured!");
+		}
+
 		Supplier<List<? extends T>> plugins = () -> factory.getBeanProvider(type, false)
 				.stream(Predicate.not(exclusions::contains))
 				.toList();
diff --git a/core/src/main/java/org/springframework/plugin/core/support/package-info.java b/core/src/main/java/org/springframework/plugin/core/support/package-info.java
index b92954d..7174d7f 100644
--- a/core/src/main/java/org/springframework/plugin/core/support/package-info.java
+++ b/core/src/main/java/org/springframework/plugin/core/support/package-info.java
@@ -2,5 +2,5 @@
  * This package contains support classes to create bean lists or plugin registry instances out of beans implementing a
  * certain interface.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.plugin.core.support;
diff --git a/pom.xml b/pom.xml
index a258ba1..6a62d3f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -46,10 +46,13 @@
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
 		<assertj.version>3.23.1</assertj.version>
+		<errorprone.version>2.36.0</errorprone.version>
 		<junit.version>5.9.1</junit.version>
 		<logback.version>1.4.4</logback.version>
 		<mockito.version>4.9.0</mockito.version>
+		<nullaway.version>0.12.3</nullaway.version>
 		<spring.version>7.0.0-SNAPSHOT</spring.version>
+		<source.level>17</source.level>
 		<slf4j.version>2.0.3</slf4j.version>
 
 		<artifactory-maven-plugin.version>3.4.0</artifactory-maven-plugin.version>
@@ -187,6 +190,65 @@
 			</distributionManagement>
 		</profile>
 
+		<profile>
+			<id>nullaway</id>
+			<build>
+				<plugins>
+					<plugin>
+						<groupId>org.apache.maven.plugins</groupId>
+						<artifactId>maven-compiler-plugin</artifactId>
+						<configuration>
+							<release>${source.level}</release>
+							<showWarnings>true</showWarnings>
+							<annotationProcessorPaths>
+								<path>
+									<groupId>com.google.errorprone</groupId>
+									<artifactId>error_prone_core</artifactId>
+									<version>${errorprone.version}</version>
+								</path>
+								<path>
+									<groupId>com.uber.nullaway</groupId>
+									<artifactId>nullaway</artifactId>
+									<version>${nullaway.version}</version>
+								</path>
+							</annotationProcessorPaths>
+						</configuration>
+						<executions>
+							<execution>
+								<id>default-compile</id>
+								<phase>none</phase>
+							</execution>
+							<execution>
+								<id>default-testCompile</id>
+								<phase>none</phase>
+							</execution>
+							<execution>
+								<id>java-compile</id>
+								<phase>compile</phase>
+								<goals>
+									<goal>compile</goal>
+								</goals>
+								<configuration>
+								<compilerArgs>
+									<arg>-XDcompilePolicy=simple</arg>
+									<arg>--should-stop=ifError=FLOW</arg>
+									<arg>-Xplugin:ErrorProne -XepDisableAllChecks -Xep:NullAway:ERROR -XepOpt:NullAway:OnlyNullMarked=true -XepOpt:NullAway:CustomContractAnnotations=org.springframework.lang.Contract</arg>
+								</compilerArgs>
+								</configuration>
+							</execution>
+							<execution>
+								<id>java-test-compile</id>
+								<phase>test-compile</phase>
+								<goals>
+									<goal>testCompile</goal>
+								</goals>
+							</execution>
+						</executions>
+					</plugin>
+				</plugins>
+			</build>
+		</profile>
+
 	</profiles>
 
 	<dependencies>
@@ -228,6 +290,12 @@
 			<version>${slf4j.version}</version>
 		</dependency>
 
+		<dependency>
+			<groupId>org.jspecify</groupId>
+			<artifactId>jspecify</artifactId>
+			<version>1.0.0</version>
+		</dependency>
+
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>jcl-over-slf4j</artifactId>