What are the effects of disabling scripting in a JSP?

Question

I recently read how to disable scripting for an entire application by adding the following elements to the web.xml file:

<jsp-config>
    <jsp-property-group>
        <url-pattern>*.jsp</url-pattern>
        <scripting-invalid>true</scripting-invalid>
    </jsp-property-group>
</jsp-config>

It went on to state that doing this forces you to always use standard JSP tags, EL, and JSTL instead of scripting, but it doesn't define 'scripting'. I was under the impression that EL is a form of scripting, and now I'm left wondering what is it I can't do exactly, after I disable scripting?

Answer 1

It disables scriptlets (<% %>), scriptlet expressions (<%= %>) and scriptlet declarations (<%! %>), which is a way of embedding raw Java code inside a JSP file. Using scriptlets has indeed been discouraged since the birth of taglibs/EL in favor of better readable and maintainable code.

See also:

• Java EE 5 tutorial - disabling scripting