diff --git a/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenBaseModifiableModelsProvider.java b/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenBaseModifiableModelsProvider.java
index 4ad84dfd5780..e1426787d388 100644
--- a/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenBaseModifiableModelsProvider.java
+++ b/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenBaseModifiableModelsProvider.java
@@ -64,7 +64,7 @@ public abstract class MavenBaseModifiableModelsProvider implements MavenModifiab
     return myModuleModel;
   }
 
-  public ModifiableRootModel getRootModel(Module module) {
+  public ModifiableRootModel getRootModel(@NotNull Module module) {
     ModifiableRootModel result = myRootModels.get(module);
     if (result == null) {
       result = doGetRootModel(module);
diff --git a/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenDefaultModifiableModelsProvider.java b/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenDefaultModifiableModelsProvider.java
index 6ad8c9d6b041..f9af5a08c854 100644
--- a/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenDefaultModifiableModelsProvider.java
+++ b/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenDefaultModifiableModelsProvider.java
@@ -32,6 +32,7 @@ import com.intellij.openapi.roots.libraries.Library;
 import com.intellij.openapi.roots.libraries.LibraryTable;
 import com.intellij.packaging.artifacts.ArtifactManager;
 import com.intellij.packaging.artifacts.ModifiableArtifactModel;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.idea.maven.utils.MavenUtil;
 
 import java.util.Collection;
@@ -65,7 +66,7 @@ public class MavenDefaultModifiableModelsProvider extends MavenBaseModifiableMod
   }
 
   @Override
-  protected ModifiableRootModel doGetRootModel(final Module module) {
+  protected ModifiableRootModel doGetRootModel(@NotNull final Module module) {
     return new ReadAction<ModifiableRootModel>() {
       protected void run(Result<ModifiableRootModel> result) throws Throwable {
         result.setResult(ModuleRootManager.getInstance(module).getModifiableModel());
diff --git a/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenRootModelAdapter.java b/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenRootModelAdapter.java
index 247bef6d208e..adee4cf84848 100644
--- a/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenRootModelAdapter.java
+++ b/plugins/maven/src/main/java/org/jetbrains/idea/maven/importing/MavenRootModelAdapter.java
@@ -46,7 +46,7 @@ public class MavenRootModelAdapter {
   private final ModifiableModuleModel myModuleModel;
   private final ModifiableRootModel myRootModel;
 
-  public MavenRootModelAdapter(MavenProject p, Module module, final MavenModifiableModelsProvider rootModelsProvider) {
+  public MavenRootModelAdapter(@NotNull MavenProject p, @NotNull Module module, final MavenModifiableModelsProvider rootModelsProvider) {
     myMavenProject = p;
     myModuleModel = rootModelsProvider.getModuleModel();
     myRootModel = rootModelsProvider.getRootModel(module);