pressions defined by Jakarta Expression Language: <i>value expressions</i>
and <i>method expressions</i>. A <a href="../../javax/el/ValueExpression.html" title="class in javax.el"><code>ValueExpression</code></a> such as 
<code>"${customer.name}"</code> can be used either
as an <i>rvalue</i> (return the value associated with property <code>name</code>
of the model object <code>customer</code>) or as an <i>lvalue</i> 
(set the value of the property <code>name</code> of the model object
<code>customer</code>)