Ensure package-info.java in each package w/ @NullMarked

spring-grpc-core/src/main/java/org/springframework/grpc/client/ClientInterceptorsConfigurer.java

@@ -37,7 +37,7 @@ public class ClientInterceptorsConfigurer implements InitializingBean {
 
 	private final ApplicationContext applicationContext;
 
-	private List<ClientInterceptor> globalInterceptors;
+	private List<ClientInterceptor> globalInterceptors = new ArrayList<>();
 
 	public ClientInterceptorsConfigurer(ApplicationContext applicationContext) {
 		this.applicationContext = applicationContext;

spring-grpc-core/src/main/java/org/springframework/grpc/client/DefaultGrpcChannelFactory.java

@@ -55,7 +55,7 @@ public class DefaultGrpcChannelFactory<T extends ManagedChannelBuilder<T>>
 
 	private final ClientInterceptorsConfigurer interceptorsConfigurer;
 
-	private ClientInterceptorFilter interceptorFilter;
+	private @Nullable ClientInterceptorFilter interceptorFilter;
 
 	private ChannelCredentialsProvider credentials = ChannelCredentialsProvider.INSECURE;
 

spring-grpc-core/src/main/java/org/springframework/grpc/client/GrpcClientFactory.java

@@ -24,8 +24,11 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
@@ -39,6 +42,7 @@
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.TypeFilter;
 import org.springframework.grpc.internal.ClasspathScanner;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
@@ -59,7 +63,7 @@ public class GrpcClientFactory implements ApplicationContextAware {
 
 	private Map<Class<?>, StubFactory<?>> factories = new LinkedHashMap<>();
 
-	private ApplicationContext context;
+	private @Nullable ApplicationContext context;
 
 	static {
 		DEFAULT_FACTORIES.add((Class<? extends StubFactory<?>>) BlockingStubFactory.class);
@@ -74,6 +78,10 @@ public void setApplicationContext(ApplicationContext applicationContext) throws
 		this.context = applicationContext;
 	}
 
+	private ApplicationContext requireNonNullContext() {
+		return Objects.requireNonNull(this.context, "ApplicationContext is required");
+	}
+
 	public <T> T getClient(String target, Class<T> type, Class<?> factory) {
 		@SuppressWarnings("unchecked")
 		StubFactory<T> stubs = (StubFactory<T>) findFactory(factory, type);
@@ -84,7 +92,7 @@ public <T> T getClient(String target, Class<T> type, Class<?> factory) {
 	private StubFactory<?> findFactory(Class<?> factoryType, Class<?> type) {
 		if (this.factories.isEmpty()) {
 			List<StubFactory<?>> factories = new ArrayList<>();
-			for (StubFactory<?> factory : this.context.getBeansOfType(StubFactory.class).values()) {
+			for (StubFactory<?> factory : this.requireNonNullContext().getBeansOfType(StubFactory.class).values()) {
 				factories.add(factory);
 			}
 			AnnotationAwareOrderComparator.sort(factories);
@@ -96,7 +104,9 @@ private StubFactory<?> findFactory(Class<?> factoryType, Class<?> type) {
 					continue;
 				}
 				this.factories.put(factory,
-						(StubFactory<?>) this.context.getAutowireCapableBeanFactory().createBean(factory));
+						(StubFactory<?>) this.requireNonNullContext()
+							.getAutowireCapableBeanFactory()
+							.createBean(factory));
 			}
 		}
 		StubFactory<?> factory = findFactory(this.factories, factoryType, type);
@@ -107,7 +117,8 @@ private StubFactory<?> findFactory(Class<?> factoryType, Class<?> type) {
 		return factory;
 	}
 
-	private static Class<?> findDefaultFactory(BeanDefinitionRegistry registry, Class<?> factoryType, Class<?> type) {
+	private static @Nullable Class<?> findDefaultFactory(BeanDefinitionRegistry registry,
+			@Nullable Class<?> factoryType, Class<?> type) {
 		if (factoryType != null && factoryType != UnspecifiedStubFactory.class) {
 			return supports(factoryType, type) ? factoryType : null;
 		}
@@ -131,6 +142,8 @@ private static Set<Class<?>> locateFactoryTypes(BeanDefinitionRegistry registry)
 		beanDefinition = (AbstractBeanDefinition) registry.getBeanDefinition(FACTORIES_BEAN_DEFINITION_NAME);
 		@SuppressWarnings("unchecked")
 		Set<Class<?>> factories = (Set<Class<?>>) beanDefinition.getAttribute("factories");
+		Assert.notEmpty(factories,
+				"The %s bean requires a 'factories' attribute".formatted(FACTORIES_BEAN_DEFINITION_NAME));
 		return factories;
 
 	}
@@ -152,7 +165,7 @@ public static HashSet<Class<?>> findStubFactoryTypes(BeanDefinitionRegistry regi
 		return factories;
 	}
 
-	private static Class<?> resolveBeanClass(BeanDefinition beanDefinition) {
+	private static @Nullable Class<?> resolveBeanClass(BeanDefinition beanDefinition) {
 		if (beanDefinition instanceof AbstractBeanDefinition rootBeanDefinition) {
 			if (rootBeanDefinition.hasBeanClass()) {
 				return rootBeanDefinition.getBeanClass();
@@ -161,6 +174,7 @@ private static Class<?> resolveBeanClass(BeanDefinition beanDefinition) {
 		return null;
 	}
 
+	@SuppressWarnings("NullAway")
 	private static boolean supports(Class<?> factory, Class<?> type) {
 		// To avoid needing to instantiate the factory we use reflection to check for a
 		// static supports() method. If it exists we call it.
@@ -186,7 +200,7 @@ private static boolean supports(Class<?> factory, Class<?> type) {
 		return supports;
 	}
 
-	private static StubFactory<?> findFactory(Map<Class<?>, StubFactory<?>> values, Class<?> factoryType,
+	private static @Nullable StubFactory<?> findFactory(Map<Class<?>, StubFactory<?>> values, Class<?> factoryType,
 			Class<?> type) {
 		StubFactory<?> factory = null;
 		if (factoryType != null && factoryType != UnspecifiedStubFactory.class) {
@@ -204,7 +218,7 @@ private static StubFactory<?> findFactory(Map<Class<?>, StubFactory<?>> values,
 	}
 
 	private GrpcChannelFactory channels() {
-		return this.context.getBean(GrpcChannelFactory.class);
+		return this.requireNonNullContext().getBean(GrpcChannelFactory.class);
 	}
 
 	public static void register(BeanDefinitionRegistry registry, GrpcClientRegistrationSpec spec) {
@@ -230,8 +244,8 @@ public static void register(BeanDefinitionRegistry registry, GrpcClientRegistrat
 		}
 	}
 
-	public record GrpcClientRegistrationSpec(String prefix, Class<? extends StubFactory<?>> factory, String target,
-			Class<?>[] types, String[] packages) {
+	public record GrpcClientRegistrationSpec(String prefix, @Nullable Class<? extends StubFactory<?>> factory,
+			String target, Class<?>[] types, String[] packages) {
 
 		private static ClasspathScanner SCANNER = new ClasspathScanner();
 
@@ -276,7 +290,7 @@ public GrpcClientRegistrationSpec(String prefix, String target, Class<?>[] types
 			this(prefix, UnspecifiedStubFactory.class, target, types, new String[0]);
 		}
 
-		public GrpcClientRegistrationSpec factory(Class<? extends StubFactory<?>> factory) {
+		public GrpcClientRegistrationSpec factory(@Nullable Class<? extends StubFactory<?>> factory) {
 			return new GrpcClientRegistrationSpec(this.prefix, factory, this.target, this.types, this.packages);
 		}
 

spring-grpc-core/src/main/java/org/springframework/grpc/client/aot/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * AOT (Ahead-Of-Time) processing for gRPC clients.
+ */
+@NullMarked
+package org.springframework.grpc.client.aot;
+
+import org.jspecify.annotations.NullMarked;

spring-grpc-core/src/main/java/org/springframework/grpc/client/interceptor/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * gRPC client interceptors.
+ */
+@NullMarked
+package org.springframework.grpc.client.interceptor;
+
+import org.jspecify.annotations.NullMarked;

spring-grpc-core/src/main/java/org/springframework/grpc/client/interceptor/security/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Security-related gRPC client interceptors.
+ */
+@NullMarked
+package org.springframework.grpc.client.interceptor.security;
+
+import org.jspecify.annotations.NullMarked;

spring-grpc-core/src/main/java/org/springframework/grpc/client/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * gRPC client infrastructure.
+ */
+@NullMarked
+package org.springframework.grpc.client;
+
+import org.jspecify.annotations.NullMarked;

spring-grpc-core/src/main/java/org/springframework/grpc/internal/ClasspathScanner.java

@@ -24,6 +24,7 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.context.ResourceLoaderAware;
@@ -49,9 +50,9 @@ public class ClasspathScanner implements ResourceLoaderAware {
 
 	private String resourcePattern = DEFAULT_RESOURCE_PATTERN;
 
-	private ResourcePatternResolver resourcePatternResolver;
+	private @Nullable ResourcePatternResolver resourcePatternResolver;
 
-	private MetadataReaderFactory metadataReaderFactory;
+	private @Nullable MetadataReaderFactory metadataReaderFactory;
 
 	@Override
 	public void setResourceLoader(ResourceLoader resourceLoader) {

spring-grpc-core/src/main/java/org/springframework/grpc/internal/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Internal utilities and helpers.
+ */
+@NullMarked
+package org.springframework.grpc.internal;
+
+import org.jspecify.annotations.NullMarked;

spring-grpc-core/src/main/java/org/springframework/grpc/server/DefaultGrpcServerFactory.java

@@ -66,23 +66,24 @@ public class DefaultGrpcServerFactory<T extends ServerBuilder<T>> implements Grp
 
 	private final List<ServerBuilderCustomizer<T>> serverBuilderCustomizers;
 
-	private KeyManagerFactory keyManager;
+	private @Nullable KeyManagerFactory keyManager;
 
-	private TrustManagerFactory trustManager;
+	private @Nullable TrustManagerFactory trustManager;
 
-	private ClientAuth clientAuth;
+	private @Nullable ClientAuth clientAuth;
 
-	private ServerServiceDefinitionFilter serviceFilter;
+	private @Nullable ServerServiceDefinitionFilter serviceFilter;
 
-	private ServerInterceptorFilter interceptorFilter;
+	private @Nullable ServerInterceptorFilter interceptorFilter;
 
 	public DefaultGrpcServerFactory(String address, List<ServerBuilderCustomizer<T>> serverBuilderCustomizers) {
 		this.address = address;
 		this.serverBuilderCustomizers = Objects.requireNonNull(serverBuilderCustomizers, "serverBuilderCustomizers");
 	}
 
 	public DefaultGrpcServerFactory(String address, List<ServerBuilderCustomizer<T>> serverBuilderCustomizers,
-			KeyManagerFactory keyManager, TrustManagerFactory trustManager, ClientAuth clientAuth) {
+			@Nullable KeyManagerFactory keyManager, @Nullable TrustManagerFactory trustManager,
+			@Nullable ClientAuth clientAuth) {
 		this(address, serverBuilderCustomizers);
 		this.keyManager = keyManager;
 		this.trustManager = trustManager;

spring-grpc-core/src/main/java/org/springframework/grpc/server/NettyGrpcServerFactory.java

@@ -21,6 +21,8 @@
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.TrustManagerFactory;
 
+import org.jspecify.annotations.Nullable;
+
 import io.grpc.TlsServerCredentials.ClientAuth;
 import io.grpc.netty.NettyServerBuilder;
 import io.netty.channel.MultiThreadIoEventLoopGroup;
@@ -38,8 +40,9 @@
 public class NettyGrpcServerFactory extends DefaultGrpcServerFactory<NettyServerBuilder> {
 
 	public NettyGrpcServerFactory(String address,
-			List<ServerBuilderCustomizer<NettyServerBuilder>> serverBuilderCustomizers, KeyManagerFactory keyManager,
-			TrustManagerFactory trustManager, ClientAuth clientAuth) {
+			List<ServerBuilderCustomizer<NettyServerBuilder>> serverBuilderCustomizers,
+			@Nullable KeyManagerFactory keyManager, @Nullable TrustManagerFactory trustManager,
+			@Nullable ClientAuth clientAuth) {
 		super(address, serverBuilderCustomizers, keyManager, trustManager, clientAuth);
 	}
 

spring-grpc-core/src/main/java/org/springframework/grpc/server/ShadedNettyGrpcServerFactory.java

@@ -21,6 +21,8 @@
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.TrustManagerFactory;
 
+import org.jspecify.annotations.Nullable;
+
 import io.grpc.TlsServerCredentials.ClientAuth;
 import io.grpc.netty.shaded.io.grpc.netty.NettyServerBuilder;
 import io.grpc.netty.shaded.io.netty.channel.epoll.EpollEventLoopGroup;
@@ -37,8 +39,9 @@
 public class ShadedNettyGrpcServerFactory extends DefaultGrpcServerFactory<NettyServerBuilder> {
 
 	public ShadedNettyGrpcServerFactory(String address,
-			List<ServerBuilderCustomizer<NettyServerBuilder>> serverBuilderCustomizers, KeyManagerFactory keyManager,
-			TrustManagerFactory trustManager, ClientAuth clientAuth) {
+			List<ServerBuilderCustomizer<NettyServerBuilder>> serverBuilderCustomizers,
+			@Nullable KeyManagerFactory keyManager, @Nullable TrustManagerFactory trustManager,
+			@Nullable ClientAuth clientAuth) {
 		super(address, serverBuilderCustomizers, keyManager, trustManager, clientAuth);
 	}
 

spring-grpc-core/src/main/java/org/springframework/grpc/server/exception/CompositeGrpcExceptionHandler.java

@@ -16,6 +16,8 @@
 
 package org.springframework.grpc.server.exception;
 
+import org.jspecify.annotations.Nullable;
+
 import io.grpc.StatusException;
 
 public class CompositeGrpcExceptionHandler implements GrpcExceptionHandler {
@@ -27,7 +29,7 @@ public CompositeGrpcExceptionHandler(GrpcExceptionHandler... exceptionHandlers)
 	}
 
 	@Override
-	public StatusException handleException(Throwable exception) {
+	public @Nullable StatusException handleException(Throwable exception) {
 		for (GrpcExceptionHandler exceptionHandler : this.exceptionHandlers) {
 			StatusException status = exceptionHandler.handleException(exception);
 			if (status != null) {