Can you try running this code? (I might have a typo; I didn't run it.) The idea is to
1) Use a bind variable so PreparedStatements are used properly
2) See if the database can find a match for that id.
The idea is to let Java handle the bind variables for you. Which is good practice and prevents people from running a SQL injection attack on your database. I don't actually think that is the reason your code isn't deleting