String s="Users.jsp?tgt1="+Add+"";(i wanted to know what should go here)
I'm not sure what you are looking for here, but
would create a URN with a query string parameter named tgt1 with the value of Add appended.
In the context of your coding style your JSP would have
and your input would be
Comments: You have two inputs outside your form in your JSP. One has
value="<%=rs.getString("DBID")%>".
indicating you do have your database code in your JSP. And based on this
<input type="Submit" style="display: none" value="Add Query"id="Query_but" onclick="invoke(2);">
you probably have your javascript code in it as well. When you get this working it would be a good idea to follow R. Jain's PS and practice some separation of concerns (SoC). You're knee deep in bear scat here.