Couldnt solve/explain this jsp/mysql error

Question

in one of my page that makes the table i have these codes :
     String a = "CREATE TABLE inv"+invId+" (";
     String b = "itemId int(5) NOT NULL, ";
     String c = "itemSerial varchar(255), ";
     String d = "itemAsset varchar(255), ";
     String e = "itemComments varchar(255), ";
     String f = "itemModel int(5) NOT NULL, ";
     String g = "itemStatus int(5) NOT NULL, ";
     String h = "itemEnterDate date NOT NULL, ";
     String i = "PRIMARY KEY (itemId))";
     String makeTB = a+b+c+d+e+f+g+h+i;
     SQLStatement3.executeQuery(makeTB);
then the other processing page is suppose to delete it :
String prefixId = request.getParameter("objectId");
String confirmId = request.getParameter("confirmId");
if (prefixId == null) {
     out.println("prefixId == null");
else if (confirmId == null) {
     out.println("confirmId == null");
else {
     String delPrefix = "Delete from itemPrefix where prefixId="+prefixId;
     SQLStatement.executeQuery(delPrefix);
     String dropTB = "Drop table inv"+prefixId;
     SQLStatement.executeQuery(dropTB);
     response.sendRedirect("invConfirm.jsp?object="+confirmId+"&msg= has being deleted.&url=invAddPrefix.jsp");
the problem is when i created the table
i checked it, and it exist so theres no problem there
but when i attempt to delete it thru running the jsp page,
i got this :
javax.servlet.ServletException: General error: Unknown table 'inv8'
before dropping the table i did a "select * from inv8" in the query of mysql and it exist
however got that msg when i try to drop that table thru jsp
(that message usually appear when the table doesnt exist only)
wierd thing is even when this error appears that table is dropped successfully too
i dont know wads causing that error to pop up
can anyone help me ?

Answer 1

Don't know if this will help but when executing DDL statements (create, drop, alter) and DML statements (insert, update, delete) you should use executeUpdate() instead of executeQuery().