Drop Down List in GWT

To achieve this, we need to work on ListBox of GWT.

public class ListBoxExample implements EntryPoint {

  public void onModuleLoad() {
    // Make a new list box, adding a few items to it.
    ListBox lb = new ListBox();
    lb.addItem("foo");
    lb.addItem("bar");
    lb.addItem("baz");
    lb.addItem("toto");
    lb.addItem("tintin");

    // Make enough room for all five items (setting this value to 1 turns it
    // into a drop-down list).
    lb.setVisibleItemCount(1);

    // Add it to the root panel.
    RootPanel.get().add(lb);
  }
}