Question

Consider this example:

<% int testNumber = 1; %>
//Some HTML goes here
<%=testNumber%>

I get compile error:

testNumber cannot be resolved to a variable

Can someone explain what is going on?

Answer 1

You need to make sure that you understand variable scoping. It’s in scriptlets the same as in normal Java classes.

So if you actually have for example

<%
   if (someCondition) {
       int testNumber = 1;
   }
%>

...

<%=testNumber%>

Then you will get exactly this error (also in a normal Java class!). To fix this, you’d need to make sure that the variable is declared in the very same scope, if necessary with a default value.

<%
   int testNumber = 0;

   if (someCondition) {
       testNumber = 1;
   }
%>

...

<%=testNumber%>

---

Unrelated to the concrete problem, using scriptlets is considered poor practice.