> I've set the SQL Connection in my Java project with setAutoCommit(false)
You need to have autoCommit true. AutoCommit false will start a local transaction.
> als tried adding a "SET AutoCommitTxn false"
You mean from the client correct? It should give you an exception when the value is not as expected. You should use SET AutoCommitTxn OFF, or set the value in your connection string.
Yes, I had SET AutoCommitTxn OFF but leaving conn.setAutoCommit to true solved the problem.