Here is the simple Demo App , you can modify it for button click event :
import java.awt.Desktop;
import java.io.File;
import java.io.IOException;
public class Test {
public static void main(String[] a) {
try {
if (Desktop.isDesktopSupported()) {
Desktop.getDesktop().open(new File("c:\\a.doc"));
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
}
This would open word file with default word application .
More detail here for Desktop