final String name = "John Doe";
final String dateOfBirth = "1976-07-12";
final String siblings = "2";
// enter values
HtmlInput nameInput = form.getInputByName("form:name");
nameInput.setValueAttribute(name);
HtmlInput dateOfBirthInput = form.getInputByName("form:dateOfBirth");
dateOfBirthInput.setValueAttribute(dateOfBirth);
HtmlInput siblingsInput = form.getInputByName("form:siblings");
siblingsInput.setValueAttribute(siblings);
// click commandButton
HtmlSubmitInput submitButton = (HtmlSubmitInput) page.getElementById("form:submit");
page = submitButton.click();