[Variable usage in java code (JRXML file)]

Hi, I would like to use variables in java code. I wanted to realise this kind of code:

    <variable name="abu"  class="java.lang.String" resetType="None">        <variableExpression><![CDATA[simpleDateFormat]]></variableExpression>    </variable>[/code]

<textFieldExpression><![CDATA[ new $V{abu}("MM/dd/yy").format($F{CLIENT_BIRTHDATE})]]></textFieldExpression></textField>[/code]

Please guide me :)