对谷歌云endpoint的理解？

Question

云-endpoint。
我正在学习Udacity教程。我对请求和响应的流程有点混淆，下面是我的理解
endpoint应该用@api注释，endpoint方法应该用@apimethod注释，这些方法不应该返回原始数据类型。下面是一个endpoint方法

@ApiMethod(name = "saveProfile", path = "profile", httpMethod = HttpMethod.POST)

public Profile saveProfile(ProfileForm profileForm) throws UnauthorizedException {

    String userId = null;
    String mainEmail = null;
    String displayName = "Your name will go here";
    TeeShirtSize teeShirtSize = TeeShirtSize.NOT_SPECIFIED;

    if(profileForm.getTeeShirtSize() != null)
        teeShirtSize = profileForm.getTeeShirtSize();

    displayName = profileForm.getDisplayName();

    Profile profile = new Profile(userId, displayName, mainEmail, teeShirtSize);

    return profile;
}

下面是我的ProfileForm和Profile类

public class ProfileForm {
private String displayName;

private TeeShirtSize teeShirtSize;

private ProfileForm () {}

    public ProfileForm(String displayName, TeeShirtSize teeShirtSize) {
    this.displayName = displayName;
    this.teeShirtSize = teeShirtSize;
}

public String getDisplayName() {
    return displayName;
}

public TeeShirtSize getTeeShirtSize() {
    return teeShirtSize;
}

public static enum TeeShirtSize {
    NOT_SPECIFIED,
    XS,
    S,
    M,
    L, 
    XL, 
    XXL,
    XXXL
  }
}

public class Profile {
String displayName;
String mainEmail;
TeeShirtSize teeShirtSize;


String userId;

    public Profile (String userId, String displayName, String mainEmail, TeeShirtSize teeShirtSize) {
    this.userId = userId;
    this.displayName = displayName;
    this.mainEmail = mainEmail;
    this.teeShirtSize = teeShirtSize;
}

public String getDisplayName() {
    return displayName;
}

public String getMainEmail() {
    return mainEmail;
}

public TeeShirtSize getTeeShirtSize() {
    return teeShirtSize;
}

public String getUserId() {
    return userId;
}

    private Profile() {}

}

Answer 1

我用的是1.9.3版本的google-app-engine，然后我改成了1.9.20，现在它工作得很好。但我仍然想问一些问题，比如为什么它不能在1.9.3中运行？
谢谢