Create function using custom UDF

[Buntu Dev]

Does the JAR need to be added for every session before using the custom UDF
created using "CREATE FUNCTION"?

I'm using Hive 0.13 and was able to add a custom UDF successfully and use
it in a sample query. But in the subsequent Hive sessions, I do see the
function but I get this error when using the function:

  FAILED: SemanticException [Error 10011]: Line 1:7 Invalid function
'my_func'

Thanks for the help!