I have the following class that implements the single Upload example
@Override
public void init() {
Window mainWindow = new Window("Singleuploadclick Application");
Label label = new Label("Hello Vaadin user");
mainWindow.addComponent(label);
status = new Label("Please select a file to upload");
upload = new Upload(null, receiver);
upload.setImmediate(true);
upload.setButtonCaption("Select file");
upload.addListener(new Upload.StartedListener() {
private static final long serialVersionUID = 1L;
@Override
public void uploadStarted(StartedEvent event) {
upload.setVisible(false);
status.setValue("Uploading file \"" + event.getFilename() + "\"");
}
});
upload.addListener(new Upload.ProgressListener() {
private static final long serialVersionUID = 1L;
@Override
public void updateProgress(long readBytes, long contentLength) {
}
});
upload.addListener(new Upload.SucceededListener() {
private static final long serialVersionUID = 1L;
@Override
public void uploadSucceeded(SucceededEvent event) {
status.setValue("Uploading file \"" + event.getFilename() + "\" succeeded");
}
});
upload.addListener(new Upload.FailedListener() {
private static final long serialVersionUID = 1L;
@Override
public void uploadFailed(FailedEvent event) {
status.setValue("Uploading interrupted");
}
});
upload.addListener(new Upload.FinishedListener() {
private static final long serialVersionUID = 1L;
@Override
public void uploadFinished(FinishedEvent event) {
upload.setVisible(true);
upload.setCaption("Select another file");
}
});
mainWindow.addComponent(status);
mainWindow.addComponent(upload);
setMainWindow(mainWindow);
}
When running the application I get strange layout display of upload component.

So i need upload component just with one upload button, that why i used : upload.setImmediate(true);