GH-1192 - Migrate code base to jSpecify for nullness verification.

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/Asciidoctor.java

@@ -25,9 +25,9 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
+import org.jspecify.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.springframework.lang.Nullable;
 import org.springframework.modulith.core.ApplicationModule;
 import org.springframework.modulith.core.ApplicationModuleDependency;
 import org.springframework.modulith.core.ApplicationModules;

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/ConfigurationProperties.java

@@ -23,9 +23,9 @@ import java.util.List;
 import java.util.Map;
 import java.util.stream.Stream;
 
+import org.jspecify.annotations.Nullable;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
-import org.springframework.lang.Nullable;
 import org.springframework.modulith.core.ApplicationModule;
 import org.springframework.modulith.docs.ConfigurationProperties.ConfigurationProperty;
 import org.springframework.util.Assert;
@@ -124,7 +124,6 @@ class ConfigurationProperties implements Iterable<ConfigurationProperty> {
 	static record ConfigurationProperty(String name, @Nullable String description, String type, String sourceType,
 			@Nullable String defaultValue) {
 
-		@SuppressWarnings("null")
 		static Stream<ConfigurationProperty> of(Map<String, Object> source) {
 
 			String sourceType = getAsString(source, "sourceType");
@@ -133,9 +132,9 @@ class ConfigurationProperties implements Iterable<ConfigurationProperty> {
 				return Stream.empty();
 			}
 
-			ConfigurationProperty property = new ConfigurationProperty(getAsString(source, "name"),
+			ConfigurationProperty property = new ConfigurationProperty(getRequiredAsString(source, "name"),
 					getAsString(source, "description"),
-					getAsString(source, "type"),
+					getRequiredAsString(source, "type"),
 					sourceType,
 					getAsString(source, "defaultValue"));
 
@@ -146,6 +145,15 @@ class ConfigurationProperties implements Iterable<ConfigurationProperty> {
 			return StringUtils.hasText(sourceType);
 		}
 
+		private static String getRequiredAsString(Map<String, Object> source, String key) {
+
+			var value = getAsString(source, key);
+
+			Assert.notNull(value, "No value found for key %s in %s!".formatted(key, source));
+
+			return value;
+		}
+
 		private static @Nullable String getAsString(Map<String, Object> source, String key) {
 
 			Object value = source.get(key);

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/Documenter.java

@@ -36,7 +36,8 @@ import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
+import org.springframework.lang.Contract;
 import org.springframework.modulith.core.ApplicationModule;
 import org.springframework.modulith.core.ApplicationModules;
 import org.springframework.modulith.core.DependencyDepth;
@@ -98,7 +99,7 @@ public class Documenter {
 
 	private boolean cleared;
 
-	private Map<ApplicationModule, Component> components;
+	private @Nullable Map<ApplicationModule, Component> components;
 
 	/**
 	 * Creates a new {@link Documenter} for the {@link ApplicationModules} created for the given modulith type in the
@@ -223,6 +224,7 @@ public class Documenter {
 	 * @return the current instance, will never be {@literal null}.
 	 * @since 1.2.2
 	 */
+	@Contract("_, _ -> this")
 	public Documenter writeAggregatingDocument(DiagramOptions diagramOptions, CanvasOptions canvasOptions) {
 
 		Assert.notNull(diagramOptions, "DiagramOptions must not be null!");
@@ -485,18 +487,19 @@ public class Documenter {
 				.forEach(it -> it.addTags(DependencyType.USES_COMPONENT.toString()));
 	}
 
+	@SuppressWarnings("null")
 	private Map<ApplicationModule, Component> getComponents(DiagramOptions options) {
 
-		if (components == null) {
+		if (this.components == null) {
 
 			this.components = modules.stream() //
 					.collect(Collectors.toMap(Function.identity(),
 							it -> container.addComponent(options.defaultDisplayName.apply(it), "", "Module")));
 
-			this.components.forEach((key, value) -> addDependencies(key, value, options));
+			components.forEach((key, value) -> addDependencies(key, value, options));
 		}
 
-		return components;
+		return this.components;
 	}
 
 	private void addComponentsToView(ApplicationModule module, ComponentView view, DiagramOptions options) {
@@ -643,6 +646,11 @@ public class Documenter {
 			Styles styles) {
 
 		var component = components.get(module);
+
+		if (component == null) {
+			throw new IllegalStateException("Couldn't find component for module %s!".formatted(module));
+		}
+
 		var selector = options.colorSelector;
 
 		// Apply custom color if configured
@@ -1061,6 +1069,7 @@ public class Documenter {
 			return new CanvasOptions(groupers, apiBase, targetFileName, hideInternals, hideEmptyLines);
 		}
 
+		@Nullable
 		String getApiBase() {
 			return apiBase;
 		}
@@ -1083,7 +1092,10 @@ public class Documenter {
 
 			// Wipe entries without any beans
 			new HashSet<>(result.keySet()).forEach(key -> {
-				if (result.get(key).isEmpty()) {
+
+				var value = result.get(key);
+
+				if (value != null && value.isEmpty()) {
 					result.remove(key);
 				}
 			});
@@ -1161,10 +1173,10 @@ public class Documenter {
 			 *
 			 * @param name must not be {@literal null} or empty.
 			 * @param predicate must not be {@literal null}.
-			 * @param description must not be {@literal null} or empty.
+			 * @param description can be {@literal null}.
 			 * @return will never be {@literal null}.
 			 */
-			public static Grouping of(String name, Predicate<SpringBean> predicate, String description) {
+			public static Grouping of(String name, Predicate<SpringBean> predicate, @Nullable String description) {
 				return new Grouping(name, predicate, description);
 			}
 

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/SpringModulithDocumentationSource.java

@@ -23,9 +23,9 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
+import org.jspecify.annotations.Nullable;
 import org.springframework.boot.json.BasicJsonParser;
 import org.springframework.core.io.Resource;
-import org.springframework.lang.Nullable;
 import org.springframework.modulith.docs.metadata.MethodMetadata;
 import org.springframework.modulith.docs.metadata.TypeMetadata;
 import org.springframework.modulith.docs.util.BuildSystemUtils;
@@ -134,28 +134,39 @@ class SpringModulithDocumentationSource implements DocumentationSource {
 	@SuppressWarnings("unchecked")
 	private static TypeMetadata typeMetadata(Map<String, Object> source) {
 
-		var methods = source.containsKey("methods")
-				? ((List<Map<String, Object>>) source.get("methods")).stream()
-						.map(SpringModulithDocumentationSource::methodMetadata)
-						.toList()
+		var sourceMethods = (List<Map<String, Object>>) source.get("methods");
+
+		var methods = sourceMethods != null
+				? sourceMethods.stream().map(SpringModulithDocumentationSource::methodMetadata).toList()
 				: Collections.<MethodMetadata> emptyList();
 
-		return new TypeMetadata(
-				source.get("name").toString(),
-				getString(source, "comment"),
-				methods);
+		var name = source.get("name");
+
+		if (name == null) {
+			throw new IllegalArgumentException("Source map does not contain a name entry! %s".formatted(source));
+		}
+
+		return new TypeMetadata(name.toString(), getString(source, "comment"), methods);
 	}
 
 	private static MethodMetadata methodMetadata(Map<String, Object> source) {
 
-		return new MethodMetadata(
-				source.get("name").toString(),
-				source.get("signature").toString(),
-				getString(source, "comment"));
+		var name = source.get("name");
+
+		if (name == null) {
+			throw new IllegalArgumentException("No name found in source map! %s".formatted(source));
+		}
+
+		var signature = source.get("signature");
+
+		if (signature == null) {
+			throw new IllegalArgumentException("No signature found in source map! %s".formatted(source));
+		}
+
+		return new MethodMetadata(name.toString(), signature.toString(), getString(source, "comment"));
 	}
 
-	@Nullable
-	private static String getString(Map<String, Object> source, String key) {
+	private static @Nullable String getString(Map<String, Object> source, String key) {
 
 		Object result = source.get(key);
 

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/metadata/MethodMetadata.java

@@ -19,7 +19,7 @@ import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.stream.Collectors;
 
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.Assert;
 
 /**

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/metadata/TypeMetadata.java

@@ -17,7 +17,7 @@ package org.springframework.modulith.docs.metadata;
 
 import java.util.List;
 
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Metadata about a Java type.

spring-modulith-docs/src/main/java/org/springframework/modulith/docs/package-info.java

@@ -1,5 +1,5 @@
 /**
  * Documentation support for Spring Modulith.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.modulith.docs;