TableExport Error ?? (NullPointerException)

Vaadin 6 / 7 / 8
1

Hi
TableExport Error …
help me.

maven dependency

    <dependency>
       <groupId>org.vaadin.addon</groupId>
       <artifactId>tableexport-for-vaadin</artifactId>
       <version>1.5.1.5</version>
    </dependency>
    <repository>
        <id>vaadin-addons</id>
        <url>http://maven.vaadin.com/vaadin-addons</url>
    </repository>

final ThemeResource export = new ThemeResource(“…/…/…/excel2.bmp”);
final Button excelExportButton = new Button(“Export”);
excelExportButton.setIcon(export);
excelExportButton.addClickListener(new Button.ClickListener() {
private ExcelExport excelExport;
private Table table = new Table(“excel”);
@Override
public void buttonClick(ClickEvent event) {
table.addContainerProperty(“Name”, String.class, null);
table.addContainerProperty(“Mag”, Float.class, null);

    // Add a row the hard way
    Object newItemId = table.addItem();
    Item row1 = table.getItem(newItemId);
    row1.getItemProperty("Name").setValue("Sirius");
    row1.getItemProperty("Mag").setValue(-1.46f);

    // Add a few other rows using shorthand addItem()
    table.addItem(new Object{"Canopus",        -0.72f}, 2);
    table.addItem(new Object{"Arcturus",       -0.04f}, 3);
    table.addItem(new Object{"Alpha Centauri", -0.01f}, 4);
    
    excelExport = new ExcelExport(table);
    excelExport.excludeCollapsedColumns();
    excelExport.setReportTitle("Excel Report");
    excelExport.setDisplayTotals(false);
    excelExport.export();
}

});

Jboss7 Error Message
09:50:02,766
[com.vaadin.server.DefaultErrorHandler]
(http-localhost-127.0.0.1-8080-7) : java.lang.NullPointerException
at com.vaadin.addon.tableexport.TableExport.sendConvertedFileToUser(TableExport.java:92) [tableexport-for-vaadin-1.5.1.5.jar:1.5.1.5]

at com.vaadin.addon.tableexport.ExcelExport.sendConverted(ExcelExport.java:378) [tableexport-for-vaadin-1.5.1.5.jar:1.5.1.5]

at com.vaadin.addon.tableexport.TableExport.export(TableExport.java:68) [tableexport-for-vaadin-1.5.1.5.jar:1.5.1.5]

at kr.co.skinfosec.admin.view.normalization.NormalizationPolicyTableEditor$4.buttonClick(NormalizationPolicyTableEditor.java:240) [classes:]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_79]

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_79]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_79]

at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.7.0_79]

at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:508) [vaadin-server-7.5.2.jar:7.5.2]

at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:198) [vaadin-server-7.5.2.jar:7.5.2]

at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:161) [vaadin-server-7.5.2.jar:7.5.2]

at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1003) [vaadin-server-7.5.2.jar:7.5.2]

at com.vaadin.ui.Button.fireClick(Button.java:393) [vaadin-server-7.5.2.jar:7.5.2]

at com.vaadin.ui.Button$1.click(Button.java:61) [vaadin-server-7.5.2.jar:7.5.2]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_79]

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_79]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_79]

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