Can not catch exception in jsp?

Question

It sames that it is not a must to catch exception potentially throwed.The following snippet can work well.But if in a standard java file ,we should catch the naming exception.How to explain this phenomena?
<%! int a=8;%>
          <%
          System.out.println("begin jsp");
          Hashtable h=new Hashtable();
          h.put(Context.INITIAL_CONTEXT_FACTORY,"org.jnp.interfaces.NamingContextFactory");
          h.put(Context.PROVIDER_URL,"jnp://127.0.0.1:1099");
          InitialContext ic=new InitialContext(h);
          CalcHome ch=(CalcHome) ic.lookup(CalcHome.JNDI_NAME);
          System.out.println("begin create cal");
          Calc c=ch.create();
          a=c.calcBonus(2,2);
          System.out.println(a);
          %>
          <%=a%>

Answer 1

But don't forget to have isErrorPage="true" or it will ignore the try/catch, at least with my server (IPlanet).
I have actually found it much nicer to have a full error page with JSP. All my JSP pages have errorPage set to an error.jsp and isErrorPage set to false.
This means no try/catch blocks anywhere muddying up code. Just the error page has all the catches. I like it.