我终于修复了它！

感谢@Kukeltje用户，他向我提示了我做错的基本事情-和@Wietlol用户，通过道德支持和相信我"来激励我进行聊天:)

Thanks to User @Kukeltje, who hinted me at basic things that i got wrong - and User @Wietlol who motivated me in the chat through moral support and 'believes in me' :)

解决方案:

..在Application.java中:

..in Application.java:

public List<Feed> sentNotifications = new ArrayList<>();

public List<String> emails = new ArrayList<>();

public List<String> words = new LinkedList<>(Arrays.asList("vuln", "banana", "pizza", "bonanza"));

public List<String> feeds = new LinkedList<>(
        Arrays.asList("http://www.kb.cert.org/vulfeed",
                "https://ics-cert.us-cert.gov/advisories/advisories.xml",
                "https://ics-cert.us-cert.gov/alerts/alerts.xml")
);

private String currentEmail;
private String currentFeed;
private String currentWord;

[...]

 public void addEmail() {
        emails.add(currentEmail);
 }

.. and gui.xhmtl:

..and gui.xhmtl:

 <!-- EMAILS -->
    <h3>Configured Emails</h3>
    <h:form>
        <h:inputText value="#{Application.currentEmail}" var="email"/>
        <h:commandButton value="Add Email" action="#{Application.addEmail}"/>
    </h:form>
    <h:form>
        <ui:repeat var="email" value="#{Application.emails}">
            <tr>
                <td>#{email}</td>

                <td>
                    <f:facet name="header">Action</f:facet>
                    <h:commandLink value="Delete" action="#{Application.rmEmail(email)}"/>
                </td>
            </tr>
            <br></br>
        </ui:repeat>
    </h:form>

注意action="#{Application.addEmail}"如何不使用参数-而是通过value="#{Application.currentEmail}"将参数传递给方法.

Notice how action="#{Application.addEmail}" does not make use of arguments- rather the parameter is handed to the method via value="#{Application.currentEmail}".

如果您是读者，也有同样的问题，请考虑以下几点:

If you, reader, have the same problem please consider these points:

• 获取/设置Bean中的每个字段
• 原始字段！
无需参数的方法即可委托"原始字段，例如我的addEmail方法

• getter/setter for each Field in the bean
• primitive fields!
• argument-less methods to 'delegate' the primitive Fields, e.g. my addEmail method

希望这个答案对有同样问题的人有用！

Hope this answer is usefull to ppl having the same issue!

问候， 皮革