apache · Pankraz76 · Jun 4, 2025
diff --git a/api/maven-api-core/src/main/java/org/apache/maven/api/services/Sources.java b/api/maven-api-core/src/main/java/org/apache/maven/api/services/Sources.java
@@ -175,11 +175,13 @@ static class ResolvedPathSource extends PathSource implements ModelSource {
         }
 
         @Override
+        @Nullable
         public Path getPath() {
             return null;
         }
 
         @Override
+        @Nullable
         public Source resolve(String relative) {
             return null;
         }

diff --git a/api/maven-api-core/src/main/java/org/apache/maven/api/services/xml/XmlReaderRequest.java b/api/maven-api-core/src/main/java/org/apache/maven/api/services/xml/XmlReaderRequest.java
@@ -207,6 +207,7 @@ public Path getRootDirectory() {
             }
 
             @Override
+            @Nullable
             public URL getURL() {
                 return null;
             }

diff --git a/api/maven-api-xml/src/main/java/org/apache/maven/api/xml/XmlNode.java b/api/maven-api-xml/src/main/java/org/apache/maven/api/xml/XmlNode.java
@@ -473,11 +473,13 @@ private record Impl(
             }
 
             @Override
+            @Nullable
             public String attribute(@Nonnull String name) {
                 return attributes.get(name);
             }
 
             @Override
+            @Nullable
             public XmlNode child(String name) {
                 if (name != null) {
                     ListIterator<XmlNode> it = children.listIterator(children.size());

diff --git a/compat/maven-artifact/pom.xml b/compat/maven-artifact/pom.xml
@@ -41,6 +41,10 @@ under the License.
       <artifactId>junit-jupiter-params</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.maven</groupId>
+      <artifactId>maven-api-annotations</artifactId>
+    </dependency>
   </dependencies>
 
   <build>

diff --git a/compat/maven-artifact/src/main/java/org/apache/maven/artifact/versioning/VersionRange.java b/compat/maven-artifact/src/main/java/org/apache/maven/artifact/versioning/VersionRange.java
@@ -26,6 +26,7 @@
 import java.util.Objects;
 import java.util.WeakHashMap;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.artifact.Artifact;
 import org.apache.maven.artifact.DefaultArtifact;
 
@@ -92,6 +93,7 @@ public VersionRange cloneOf() {
      * @return a new {@link VersionRange} object that represents the spec
      * @throws InvalidVersionSpecificationException if invalid version specification
      */
+    @Nullable
     public static VersionRange createFromVersionSpec(String spec) throws InvalidVersionSpecificationException {
         if (spec == null) {
             return null;
@@ -202,6 +204,7 @@ private static Restriction parseRestriction(String spec) throws InvalidVersionSp
         return restriction;
     }
 
+    @Nullable
     public static VersionRange createFromVersion(String version) {
         if (DefaultArtifact.empty(version)) {
             return null;

diff --git a/compat/maven-embedder/src/main/java/org/apache/maven/cli/ResolveFile.java b/compat/maven-embedder/src/main/java/org/apache/maven/cli/ResolveFile.java
@@ -21,11 +21,15 @@
 import java.io.File;
 import java.nio.file.Paths;
 
+import org.apache.maven.api.annotations.Nullable;
+
 /**
  * Resolve relative file path against the given base directory
  */
 @Deprecated
 public class ResolveFile {
+
+    @Nullable
     public static File resolveFile(File file, String baseDirectory) {
         if (file == null) {
             return null;

diff --git a/compat/maven-embedder/src/main/java/org/apache/maven/cli/logging/Slf4jStdoutLogger.java b/compat/maven-embedder/src/main/java/org/apache/maven/cli/logging/Slf4jStdoutLogger.java
@@ -20,6 +20,7 @@
 
 import java.io.PrintStream;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.Marker;
 
@@ -61,6 +62,7 @@ public void error(String msg, Throwable t) {
     //
     // Don't need any of this
     //
+    @Nullable
     public String getName() {
         return null;
     }

diff --git a/compat/maven-embedder/src/main/java/org/apache/maven/cli/props/MavenProperties.java b/compat/maven-embedder/src/main/java/org/apache/maven/cli/props/MavenProperties.java
@@ -44,6 +44,7 @@
 import java.util.Set;
 import java.util.function.UnaryOperator;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.impl.model.DefaultInterpolator;
 
 /**
@@ -272,6 +273,7 @@ void putAllSubstituted(Map<? extends String, ? extends String> m) {
         storage.putAll(m);
     }
 
+    @Nullable
     public String put(String key, List<String> commentLines, List<String> valueLines) {
         commentLines = new ArrayList<>(commentLines);
         valueLines = new ArrayList<>(valueLines);
@@ -305,6 +307,7 @@ public String put(String key, List<String> commentLines, List<String> valueLines
         return storage.put(key, property[1]);
     }
 
+    @Nullable
     public String put(String key, List<String> commentLines, String value) {
         commentLines = new ArrayList<>(commentLines);
         this.layout.put(key, new Layout(commentLines, null));
@@ -843,6 +846,7 @@ public PropertiesReader(Reader reader, boolean maybeTyped) {
          *
          * @throws IOException in case of an I/O error
          */
+        @Nullable
         public String readProperty() throws IOException {
             commentLines.clear();
             valueLines.clear();

diff --git a/...del-builder/src/main/java/org/apache/maven/model/building/DefaultModelBuildingResult.java b/...del-builder/src/main/java/org/apache/maven/model/building/DefaultModelBuildingResult.java
@@ -24,6 +24,7 @@
 import java.util.Map;
 import java.util.Objects;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.Model;
 import org.apache.maven.model.Profile;
 
@@ -81,11 +82,13 @@ public DefaultModelBuildingResult addModelId(String modelId) {
     }
 
     @Override
+    @Nullable
     public Model getRawModel() {
         return rawModels.get(modelIds.get(0));
     }
 
     @Override
+    @Nullable
     public Model getRawModel(String modelId) {
         return rawModels.get(modelId);
     }
@@ -100,6 +103,7 @@ public DefaultModelBuildingResult setRawModel(String modelId, Model rawModel) {
     }
 
     @Override
+    @Nullable
     public List<Profile> getActivePomProfiles(String modelId) {
         return activePomProfiles.get(modelId);
     }

diff --git a/...at/maven-model-builder/src/main/java/org/apache/maven/model/building/FileModelSource.java b/...at/maven-model-builder/src/main/java/org/apache/maven/model/building/FileModelSource.java
@@ -23,6 +23,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.building.FileSource;
 
 /**
@@ -58,6 +59,7 @@ public File getPomFile() {
     }
 
     @Override
+    @Nullable
     public ModelSource2 getRelatedSource(String relPath) {
         relPath = relPath.replace('\\', File.separatorChar).replace('/', File.separatorChar);
 

diff --git a/...n-model-builder/src/main/java/org/apache/maven/model/building/ModelBuildingException.java b/...n-model-builder/src/main/java/org/apache/maven/model/building/ModelBuildingException.java
@@ -23,6 +23,7 @@
 import java.util.Collections;
 import java.util.List;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.Model;
 
 /**
@@ -87,6 +88,7 @@ public ModelBuildingResult getResult() {
      *
      * @return The erroneous model or {@code null} if not available.
      */
+    @Nullable
     public Model getModel() {
         if (result == null) {
             return null;

diff --git a/...builder/src/main/java/org/apache/maven/model/interpolation/BuildTimestampValueSource.java b/...builder/src/main/java/org/apache/maven/model/interpolation/BuildTimestampValueSource.java
@@ -21,6 +21,7 @@
 import java.util.Date;
 import java.util.Properties;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.codehaus.plexus.interpolation.AbstractValueSource;
 
 /**
@@ -36,6 +37,7 @@ class BuildTimestampValueSource extends AbstractValueSource {
     }
 
     @Override
+    @Nullable
     public Object getValue(String expression) {
         if ("build.timestamp".equals(expression) || "maven.build.timestamp".equals(expression)) {
             return mavenBuildTimestamp.formattedTimestamp();

diff --git a/...el-builder/src/main/java/org/apache/maven/model/interpolation/ObjectBasedValueSource.java b/...el-builder/src/main/java/org/apache/maven/model/interpolation/ObjectBasedValueSource.java
@@ -34,6 +34,7 @@
  * limitations under the License.
  */
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.interpolation.reflection.ReflectionValueExtractor;
 import org.codehaus.plexus.interpolation.AbstractValueSource;
 
@@ -71,6 +72,7 @@ public ObjectBasedValueSource(Object root) {
      * <p><b>NOTE:</b> The object-graph navigation actually takes place via the
      * {@link ReflectionValueExtractor} class.</p>
      */
+    @Nullable
     public Object getValue(String expression) {
         if (expression == null || expression.trim().isEmpty()) {
             return null;

diff --git a/...lder/src/main/java/org/apache/maven/model/interpolation/PathTranslatingPostProcessor.java b/...lder/src/main/java/org/apache/maven/model/interpolation/PathTranslatingPostProcessor.java
@@ -22,6 +22,7 @@
 import java.util.Collection;
 import java.util.List;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.path.PathTranslator;
 import org.codehaus.plexus.interpolation.InterpolationPostProcessor;
 import org.codehaus.plexus.interpolation.util.ValueSourceUtils;
@@ -50,6 +51,7 @@ class PathTranslatingPostProcessor implements InterpolationPostProcessor {
     }
 
     @Override
+    @Nullable
     public Object execute(String expression, Object value) {
         if (value != null) {
             expression = ValueSourceUtils.trimPrefix(expression, expressionPrefixes, true);

diff --git a/...der/src/main/java/org/apache/maven/model/interpolation/StringSearchModelInterpolator.java b/...der/src/main/java/org/apache/maven/model/interpolation/StringSearchModelInterpolator.java
@@ -30,6 +30,7 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.InputLocation;
 import org.apache.maven.model.Model;
 import org.apache.maven.model.building.ModelBuildingRequest;
@@ -124,6 +125,7 @@ private static final class InterpolateObjectAction {
             this.problems = problems;
         }
 
+        @Nullable
         public Object run() {
             while (!interpolationTargets.isEmpty()) {
                 Object obj = interpolationTargets.removeFirst();

diff --git a/...ilder/src/main/java/org/apache/maven/model/interpolation/UrlNormalizingPostProcessor.java b/...ilder/src/main/java/org/apache/maven/model/interpolation/UrlNormalizingPostProcessor.java
@@ -21,6 +21,7 @@
 import java.util.HashSet;
 import java.util.Set;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.path.UrlNormalizer;
 import org.codehaus.plexus.interpolation.InterpolationPostProcessor;
 
@@ -52,6 +53,7 @@ class UrlNormalizingPostProcessor implements InterpolationPostProcessor {
     }
 
     @Override
+    @Nullable
     public Object execute(String expression, Object value) {
         if (value != null && URL_EXPRESSIONS.contains(expression)) {
             return normalizer.normalize(value.toString());

diff --git a/...model-builder/src/main/java/org/apache/maven/model/interpolation/reflection/ClassMap.java b/...model-builder/src/main/java/org/apache/maven/model/interpolation/reflection/ClassMap.java
@@ -23,6 +23,8 @@
 import java.util.Hashtable;
 import java.util.Map;
 
+import org.apache.maven.api.annotations.Nullable;
+
 /**
  * A cache of introspection information for a specific class instance.
  * Keys {@link Method} objects by a concatenation of the
@@ -81,6 +83,7 @@ Class<?> getCachedClass() {
      * @return The found method.
      * @throws MethodMap.AmbiguousException in case of duplicate methods.
      */
+    @Nullable
     public Method findMethod(String name, Object... params) throws MethodMap.AmbiguousException {
         String methodKey = makeMethodKey(name, params);
         Object cacheEntry = methodCache.get(methodKey);

diff --git a/...c/main/java/org/apache/maven/model/interpolation/reflection/ReflectionValueExtractor.java b/...c/main/java/org/apache/maven/model/interpolation/reflection/ReflectionValueExtractor.java
@@ -82,6 +82,7 @@ public int skipChar() {
             return idx < expression.length() ? expression.charAt(idx++) : EOF;
         }
 
+        @Nullable
         public String nextToken(char delimiter) {
             int start = idx;
 
@@ -97,6 +98,7 @@ public String nextToken(char delimiter) {
             return expression.substring(start, idx++);
         }
 
+        @Nullable
         public String nextPropertyName() {
             final int start = idx;
 
@@ -162,6 +164,7 @@ public static Object evaluate(@Nonnull String expression, @Nullable Object root)
      * @return the object defined by the expression
      * @throws IntrospectionException if any
      */
+    @Nullable
     public static Object evaluate(@Nonnull String expression, @Nullable Object root, boolean trimRootToken)
             throws IntrospectionException {
         Object value = root;

diff --git a/...lder/src/main/java/org/apache/maven/model/path/ProfileActivationFilePathInterpolator.java b/...lder/src/main/java/org/apache/maven/model/path/ProfileActivationFilePathInterpolator.java
@@ -25,6 +25,7 @@
 import java.io.File;
 import java.nio.file.Path;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.ActivationFile;
 import org.apache.maven.model.profile.ProfileActivationContext;
 import org.apache.maven.model.root.RootLocator;
@@ -64,6 +65,7 @@ public ProfileActivationFilePathInterpolator setRootLocator(RootLocator rootLoca
      *
      * @return absolute path or {@code null} if the input was {@code null}
      */
+    @Nullable
     public String interpolate(String path, ProfileActivationContext context) throws InterpolationException {
         if (path == null) {
             return null;
@@ -75,7 +77,9 @@ public String interpolate(String path, ProfileActivationContext context) throws
 
         if (basedir != null) {
             interpolator.addValueSource(new AbstractValueSource(false) {
+
                 @Override
+                @Nullable
                 public Object getValue(String expression) {
                     if ("basedir".equals(expression) || "project.basedir".equals(expression)) {
                         return basedir.getAbsolutePath();
@@ -88,7 +92,9 @@ public Object getValue(String expression) {
         }
 
         interpolator.addValueSource(new AbstractValueSource(false) {
+
             @Override
+            @Nullable
             public Object getValue(String expression) {
                 if ("project.rootDirectory".equals(expression)) {
                     Path base = basedir != null ? basedir.toPath() : null;

diff --git a/...-model-builder/src/test/java/org/apache/maven/model/building/DefaultModelBuilderTest.java b/...-model-builder/src/test/java/org/apache/maven/model/building/DefaultModelBuilderTest.java
@@ -18,6 +18,7 @@
  */
 package org.apache.maven.model.building;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.model.Dependency;
 import org.apache.maven.model.Parent;
 import org.apache.maven.model.Repository;
@@ -111,11 +112,13 @@ public ModelSource resolveModel(String groupId, String artifactId, String versio
         }
 
         @Override
+        @Nullable
         public ModelSource resolveModel(Parent parent) throws UnresolvableModelException {
             return null;
         }
 
         @Override
+        @Nullable
         public ModelSource resolveModel(Dependency dependency) throws UnresolvableModelException {
             return null;
         }

diff --git a/...t/maven-plugin-api/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptor.java b/...t/maven-plugin-api/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptor.java
@@ -35,6 +35,7 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import org.apache.maven.api.annotations.Nullable;
 import org.apache.maven.api.plugin.descriptor.lifecycle.Lifecycle;
 import org.apache.maven.api.plugin.descriptor.lifecycle.LifecycleConfiguration;
 import org.apache.maven.artifact.Artifact;
@@ -320,6 +321,7 @@ public int hashCode() {
         return 10 + getId().hashCode();
     }
 
+    @Nullable
     public MojoDescriptor getMojo(String goal) {
         if (getMojos() == null) {
             return null; // no mojo in this POM
@@ -415,6 +417,7 @@ public void setPluginArtifact(Artifact pluginArtifact) {
         this.pluginArtifact = pluginArtifact;
     }
 
+    @Nullable
     public Lifecycle getLifecycleMapping(String lifecycleId) throws IOException, XMLStreamException {
         return getLifecycleMappings().get(lifecycleId);
     }