Exporting Data To Excel Using XSSFWorkbook Class

I have to export data to excel using XSSFWorkbook

I am having error javax.el.ELException: java.lang.OutOfMemoryError: Java heap space now i what to modify my code to BigGridDemo.java

org.apache.poi.xssf.usermodel.examples: BigGridDemo.java
POI - User - HSSF and XSSF memory usage, some numbers

How can i modify my code to BigGridDemo.java

Java Code:

import com.bea.common.security.xacml.context.Result;
import com.sun.jmx.snmp.Timestamp;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;

[Code] ....

Currently am geting this error with above code

<FileDownloadActionListener> <processAction>
javax.el.ELException: java.lang.OutOfMemoryError: Java heap space
at com.sun.el.parser.AstValue.invoke(Unknown Source)
at com.sun.el.MethodExpressionImpl.invoke(Unknown Source)

[Code] ......