import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class Test  {
	public static void main(String[] args) throws Exception {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		HSSFWorkbook book = new HSSFWorkbook();
		book.createSheet("TEST");
		HSSFSheet sheet = book.cloneSheet(0);
		book.setSheetName(1,"CLONE");
		sheet.createRow(0).createCell((short)0).setCellValue("Test");
		book.write(out);
		
		book = new HSSFWorkbook(new ByteArrayInputStream(out.toByteArray()));
		sheet = book.getSheet("CLONE");
		HSSFRow row = sheet.getRow(0);
		HSSFCell cell = row.getCell((short)0);
		System.out.println(cell.getStringCellValue());
	
	}
}