Your stored procedure worked without problems for me. I can only replicate the first error if I deliberately removed “out” from par2’s definition and updated the stored procedure.
Thanks mgross, I found I had a problem of stored procedure naming: I was used to naming my objects as database.schema.objectname in MS SQL Server and I was trying to replicate that in MySql. I found that, even if MySql accepts it (e.g. you get the data you want if you work in Workbench), the JDBC driver doesn’t like it, I suppose: you get errors like I reported, which are very difficult to debug.
Moreover my first attempt to solve that naming problem was just to add a procedure with name logs_test, while keeping also the logs.test routine in the object tree, and that was a big mistake: I think, the JDBC driver was confused by the two similar names. After deleting the logs.test object, it started running ok.