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> ## Expressions

> A JSP expression is used to insert the value of a scripting language expression, converted into a string, into the data stream returned to the client. When the scripting language is the Java programming language, an expression is transformed into a statement that converts the value of the expression into a `String` object and inserts it into the implicit `out` object.

> The syntax for an expression is as follows:

>     <%= scripting language expression %>

> Note that a semicolon is not allowed within a JSP expression, even if the same expression has a semicolon when you use it within a scriptlet.

> In the web service version of the `hello1` application, `response.jsp` contains the following scriptlet, which gets the proxy that implements the service endpoint interface. It then invokes the `sayHello` method on the proxy, passing the user name retrieved from a request parameter:

>     <%
>       String resp = null;
>       try {
>         Hello hello = new HelloService().getHelloPort();
>         resp = hello.sayHello(request.getParameter("username"));
>       } catch (Exception ex) {
>         resp = ex.toString();
>       }
>     %>

> A scripting expression is then used to insert the value of `resp` into the output stream:

>     <h2><font color="black"><%= resp %>!</font></h2>