无法在Firebase数据库中插入记录

Question

好吧，我是Firebase开发的新手，我正在尝试将数据插入到已连接到我的android studio项目的应用数据库中。但是，在单击将文本添加到数据库的按钮后，我得到了这个堆栈跟踪：

E/AndroidRuntime: FATAL EXCEPTION: main
                      Process: com.xxx.xxxxx, PID: 13243
                      com.google.firebase.database.DatabaseException: Found conflicting getters for name: isChangingConfigurations
                          at com.google.android.gms.internal.zzbqi$zza.<init>(Unknown Source)
                          at com.google.android.gms.internal.zzbqi.zzi(Unknown Source)
                          at com.google.android.gms.internal.zzbqi.zzax(Unknown Source)
                          at com.google.android.gms.internal.zzbqi.zzaw(Unknown Source)
                          at com.google.firebase.database.DatabaseReference.zza(Unknown Source)
                          at com.google.firebase.database.DatabaseReference.setValue(Unknown Source)
                          at com.xxx.xxxxx.MainActivity$1.onClick(MainActivity.java:85)
                          at android.view.View.performClick(View.java:4780)
                          at android.view.View$PerformClick.run(View.java:19866)
                          at android.os.Handler.handleCallback(Handler.java:739)
                          at android.os.Handler.dispatchMessage(Handler.java:95)
                          at android.os.Looper.loop(Looper.java:135)
                          at android.app.ActivityThread.main(ActivityThread.java:5254)
                          at java.lang.reflect.Method.invoke(Native Method)
                          at java.lang.reflect.Method.invoke(Method.java:372)
                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

MainActivity代码行如果在又名第85行爆发，则如下：

mDatabase.child("users").child(mUserId).child("items").push().child("title").setValue(new ChatMessage(input.getText().toString(), mFirebaseAuth.getCurrentUser().getDisplayName()));

如果有人能够提出一个很好的快速解决方案，我将不胜感激。 Google Firebase团队前来救援！

修改

根据@Frank的请求，这是我在setValue（）中使用的ChatMessage的java类：

package com.xxx.xxxxx;

import android.support.v7.app.AppCompatActivity;
import com.google.firebase.database.IgnoreExtraProperties;
import java.util.Date;


/**
 * Created by sahir on 12/4/2016.
 */
@IgnoreExtraProperties
public class ChatMessage extends AppCompatActivity {

    public String messageText;
    public String messageUser;
    public long messageTime;

    public ChatMessage(){}

    public ChatMessage(String messageText, String messageUser) {
        this.messageText = messageText;
        this.messageUser = messageUser;

        // Initialize to current time
        messageTime = new Date().getTime();
    }

    public String getMessageText() { return messageText; }
    public String getMessageUser() { return messageUser; }
    public long getMessageTime() { return messageTime; }


}//close ChatMessage