diff --git a/platform/projectModel-api/src/com/intellij/openapi/roots/OrderEntry.java b/platform/projectModel-api/src/com/intellij/openapi/roots/OrderEntry.java
index 70822826afe4..3e159c991dab 100644
--- a/platform/projectModel-api/src/com/intellij/openapi/roots/OrderEntry.java
+++ b/platform/projectModel-api/src/com/intellij/openapi/roots/OrderEntry.java
@@ -17,10 +17,7 @@ package com.intellij.openapi.roots;
 
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.vfs.VirtualFile;
-import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.Nls;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.*;
 
 /**
  * Represents an entry in the classpath of a module (as shown in the "Order/Export" page
@@ -83,5 +80,5 @@ public interface OrderEntry extends Synthetic, Comparable<OrderEntry> {
    * @param initialValue the default value to be returned by the visit process.
    * @return the value returned by the visitor.
    */
-  <R> R accept(@NotNull RootPolicy<R> policy, @Nullable R initialValue);
+  <R> @UnknownNullability R accept(@NotNull RootPolicy<R> policy, @Nullable R initialValue);
 }
diff --git a/platform/projectModel-impl/src/com/intellij/openapi/roots/JavadocOrderRootType.java b/platform/projectModel-impl/src/com/intellij/openapi/roots/JavadocOrderRootType.java
index 4036ae459609..129d33057237 100644
--- a/platform/projectModel-impl/src/com/intellij/openapi/roots/JavadocOrderRootType.java
+++ b/platform/projectModel-impl/src/com/intellij/openapi/roots/JavadocOrderRootType.java
@@ -1,6 +1,7 @@
 // Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.openapi.roots;
 
+import com.intellij.util.ArrayUtilRt;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
@@ -33,6 +34,7 @@ public class JavadocOrderRootType extends PersistentOrderRootType {
     }
   };
   public static String @NotNull [] getUrls(@NotNull OrderEntry entry) {
-    return entry.accept(GET_JAVADOC_URL_POLICY, null);
+    String[] result = entry.accept(GET_JAVADOC_URL_POLICY, null);
+    return (result == null) ? ArrayUtilRt.EMPTY_STRING_ARRAY : result;
   }
 }