public java.lang.String getProductCategory() {
      java.lang.Object ref = productCategory_;
      if (!(ref instanceof java.lang.String)) {
        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        productCategory_ = s;
        return s;
      } else {
        return (java.lang.String) ref;
      }
    }
<pre>
Immutable. The category for the product identified by the reference image.
This should be one of "homegoods-v2", "apparel-v2", "toys-v2",
"packagedgoods-v1" or "general-v1". 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>

@return The productCategory.
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/Product.java