private void ensureProductLabelsIsMutable() {
      if (!((bitField0_ & 0x00000010) != 0)) {
        productLabels_ =
            new java.util.ArrayList<com.google.cloud.vision.v1p4beta1.Product.KeyValue>(
                productLabels_);
        bitField0_ |= 0x00000010;
      }
    }
<pre>
Immutable. The category for the product identified by the reference image.
This should be either "homegoods-v2", "apparel-v2", or "toys-v2". The
legacy categories "homegoods", "apparel", and "toys" are still supported,
but these should not be used for new products.
</pre>

<code>string product_category = 4 [(.google.api.field_behavior) = IMMUTABLE];</code>

@param value The bytes for productCategory to set.
@return This builder for chaining.
java-vision/proto-google-cloud-vision-v1p4beta1/src/main/java/com/google/cloud/vision/v1p4beta1/Product.java