If non-<code>null</code> return it.  If
 <code>null</code>, see if we have a <a href="../../../javax/el/ValueExpression.html" title="class in javax.el"><code>ValueExpression</code></a> for
 the <code>value</code> property.  If so, return the result of
 evaluating the property, otherwise return <code>null</code>.
 Note that because the specification for <a href="../../../javax/faces/component/UIComponent.html#setValueBinding-java.lang.String-javax.faces.el.ValueBinding-"><code>UIComponent.setValueBinding(jav