Java/GWT/DisclosurePanel

Use DisclosurePanel

package com.jexp.gwt.client;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.ClickListener;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.Widget;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.DisclosurePanel;
public class GWTClient implements EntryPoint{
  public void onModuleLoad() {
    DisclosurePanel disc = new DisclosurePanel("Click to disclose something:");
    disc.setContent(new HTML("This widget is is shown and hidden<br>by the "
        + "disclosure panel that wraps it."));

    RootPanel.get().add(disc);
  }
}