Exception in thread "main" java.lang.IllegalArgumentException: Argument cannot be null

</pre><p></p><pre name="code" class="html" style="font-size: 13.3333px;">Exception in thread "main" java.lang.IllegalArgumentException: Argument cannot be null
at org.eclipse.swt.SWT.error(SWT.java:4378)
at org.eclipse.swt.SWT.error(SWT.java:4312)
at org.eclipse.swt.SWT.error(SWT.java:4283)
at org.eclipse.swt.widgets.Widget.error(Widget.java:472)
at org.eclipse.swt.widgets.Text.setText(Text.java:2241)
at com.SearchMain$3.widgetSelected(SearchMain.java:113)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:248)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1057)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4170)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3759)
at com.SearchMain.main(SearchMain.java:131)

sButton.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent e) {

DirectoryDialog filedlg = new DirectoryDialog(shell, SWT.OPEN
| SWT.SAVE);
filedlg.setText("请选择jar包路径");
// filedlg.setFilterExtensions(new String[] {});
String path = filedlg.open();
if (path != null) // 不加为空判断会报上面错误
url.setText(path);
}
});