The value of variable displayed as null instead of formatted date - jasper-reports

Question

Hello I'm having issues displaying a string date of this format "01-Nov-16" as "01-11-2016" null is what's returned. I have tried all I know. Below is my exact xml.
<variable name="S_DATE" class="java.util.Date">
<variableExpression><![CDATA[new java.text.SimpleDateFormat("dd-MMM-yy",java.util.Locale.US).parse($P{startdate})]]></variableExpression>
</variable>
<textField isStretchWithOverflow="true" pattern="dd-MM-yyyy" isBlankWhenNull="false">
<reportElement stretchType="RelativeToTallestObject" x="205" y="0" width="102" height="20" isRemoveLineWhenBlank="true" isPrintWhenDetailOverflows="true" forecolor="#000000" uuid="560349d8-0bb8-44f0-90ce-41ffb71544cc"/>
<textElement textAlignment="Left">
<font size="10"/>
</textElement>
<textFieldExpression><![CDATA[$V{S_DATE}]]></textFieldExpression>
</textField>
The type of startdate parameter is String

Answer 1

First approach
Try to use parameter instead of variable. No need to use the "power" and features of variables in this case.
Sample
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="Format date" pageWidth="595" pageHeight="842" whenNoDataType="AllSectionsNoDetail" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20">
<property name="com.jaspersoft.studio.data.defaultdataadapter" value="One Empty Record"/>
<parameter name="dateAsString" class="java.lang.String">
<defaultValueExpression><![CDATA["01-Nov-2016"]]></defaultValueExpression>
</parameter>
<parameter name="dateParam" class="java.util.Date">
<defaultValueExpression><![CDATA[new SimpleDateFormat("dd-MMM-yy", Locale.US).parse($P{dateAsString})]]></defaultValueExpression>
</parameter>
<title>
<band height="79" splitType="Stretch">
<textField pattern="dd-MM-yyyy">
<reportElement x="130" y="20" width="250" height="30"/>
<textFieldExpression><![CDATA[$P{dateParam}]]></textFieldExpression>
</textField>
</band>
</title>
</jasperReport>
Output result
The result in Jaspersoft Studio will be:
Second approach
Change the resetType of the variable. The valid type for your case will be None. The right expression will be:
<variable name="S_DATE" class="java.util.Date" resetType="None">
<variableExpression><![CDATA[new SimpleDateFormat("dd-MMM-yy", Locale.US).parse($P{startdate})]]></variableExpression>
</variable>