No Exception thrown when there is a constraint violation, and delete fails

I am trying to do a delete, and there seems to be a constraint violation.
Fine, but why does it not send an exception to let me know this.  
I mean, nothing happens. Not even a warning.

Is there something I need to turn on to find constraint violations as exceptions?


Code: 
Connection c = DriverManager.getConnection(
c.setAutoCommit(true);
	
PreparedStatement pst = c.prepareStatement("delete from queue where id=?");
pst.setInt(1, 850);			
pst.executeUpdate();
			
c.close();


Exception: 
None, not a thing.


Error Log:

ERROR:  update or delete on "queue" violates foreign key constraint "fkd73c6034ba977309" on "branch_queue"
DETAIL:  Key (id)=(850) is still referenced from table "branch_queue".