When all scriptlet fragments in a given translation unit are combined in the order they appear 
in the JSP page, they shall yield a valid statement or sequence thereof, in the specified 
scripting language.
If you want to use the 
%>
 character sequence as literal characters in a scriptlet, rather than to 
end the scriptlet, you can escape them by typing 
%\>
.
Examples
Here is a simple example where the page changed dynamically depending on the time of day.
<% if (Calendar.getInstance().get(Calendar.AM_PM) == Calendar.AM) {%>
Good Morning
<% } else { %>
Good Afternoon
<% } %>
Syntax
<% 
scriptlet
 %>
2.10.3
Expressions
An expression element in a JSP page is a scripting language expression that is evaluated and 
the result is coerced to a 
String
 which is subsequently emitted into the current 
out
JspWriter
 object.
If the result of the expression cannot be coerced to a 
String 
then either a translation time 
error shall occur, or, if the coercion cannot be detected during translation, a 
ClassCastException
 shall be raised at request time.
A scripting language may support side effects in expressions. If so, they take effect when the 
expression is evaluated. Expressions are evaluated left to right in the JSP page. If the 
expressions appear in more than one run time attribute, they are evaluated left to right in the 
tag. An expression might change the value of the 
out
 object, although this is not something 
to be done lightly.
The contents of an expression must be a complete expression in the scripting language in 
which they are written. 
Expressions are evaluated at HTTP processing time. The value of an expression is converted 
to a String and inserted at the proper position in the .
jsp
 file. 
Chapter 2
Standard Syntax and Semantics
56




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