public Builder setProductCategoryBytes(com.google.protobuf.ByteString value) {
      if (value == null) {
        throw new NullPointerException();
      }
      checkByteStringIsUtf8(value);
      productCategory_ = value;
      bitField0_ |= 0x00000008;
      onChanged();
      return this;
    }
<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>

@param value The bytes for productCategory to set.
@return This builder for chaining.
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/Product.java