Loading and querying a Spark machine learning model outside of Spark
If PMML supports the model you're trying to express, it's probably the best option. Spark has some partial support for exporting as PMML. Look into JPMML + OpenScoring to score the PMML in an embedded instance.

There are loads of tools in this space that implement something like this, but they're typically entwined with their own formats or model management system.