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