Creating java UDF for Spark SQL

[sm1274]

Hello, 

I have created a sample java UDF which masks few characters of a string. However I facing couple of issues when uploading and using it.

First I could only import it, which for now is OK. But when do the following,

create function udf_mask as 'baffleCrypto' using jar '/Workspace/Users/sumandra@baffle.io/baffle-databricks-udf-1.0-SNAPSHOT.jar' 
Throws an error 
[NOT_SUPPORTED_WITH_DB_SQL] CREATE FUNCTION is not supported on a SQL warehouse.

Is there an example on how to load a jar and then use it as external function. I followed the this guide 
https://docs.databricks.com/en/sql/language-manual/sql-ref-syntax-ddl-create-function.html

Even cut-n-paste errors out. 

Any ideas?