DEVX-813: adding null checks

Author: ShipilA

commercetools/commercetools-importapi-utils/src/main/java/com/commercetools/sdk/ProductUtil.java

@@ -139,6 +139,7 @@ private static ProductVariantDraftImport extractProductVariantDraftImport(Produc
     }
 
     public static @NotNull List<Image> toImportImages(List<com.commercetools.api.models.common.Image> images) {
+        if (images == null) return null;
         return images.stream()
                 .map(i -> Image.builder()
                         .dimensions(

commercetools/commercetools-importapi-utils/src/main/java/com/commercetools/sdk/ProductVariantUtil.java

@@ -4,6 +4,8 @@
 import static com.commercetools.sdk.CommonImportUtil.importAssets;
 import static com.commercetools.sdk.ProductUtil.toImportImages;
 
+import java.util.Arrays;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 import com.commercetools.api.models.product.ProductProjection;
@@ -12,14 +14,20 @@
 
 public class ProductVariantUtil {
     public ProductVariantImport toProductVariantImport(ProductProjection product, ProductVariant variant) {
+        return toProductVariantImport(product, variant, false);
+    }
+    public ProductVariantImport toProductVariantImport(ProductProjection product, ProductVariant variant, Boolean staged) {
         return ProductVariantImport.builder()
                 .key(variant.getKey()) // required field
                 .sku(variant.getSku())
                 .isMasterVariant(variant.getId().equals(product.getMasterVariant().getId())) // required field
                 .attributes(
-                    variant.getAttributes().stream().map(ProductUtil::mapAttribute).collect(Collectors.toList()))
+                        Optional.ofNullable(variant.getAttributes())
+                                .map(attrs -> attrs.stream().map(ProductUtil::mapAttribute).collect(Collectors.toList()))
+                                .orElse(null))
                 .images(toImportImages(variant.getImages()))
                 .assets(importAssets(variant.getAssets()))
+                .staged(staged)
                 .product(p -> p.key(product.getKey())) // required field
                 .build();
     }