JasperReports JRXML Using variable/parameter JavaCollection as datasource

I'm trying to embed JRBeanJavaCollectionDataSource in jrxml. I want to display table. In jrxml I wrote:

<datasetRun subDataset="Table Dataset 1">
    <dataSourceExpression>
        <![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($V{project})]]>
    </dataSourceExpression>`
</datasetRun>

$V{project} must contain javaCollection. I don't know how to write multiple line java code in variable expression in IReport 4.5 to get my javaCollection.It is possible? Or there is another way to get javaCollection