Get java.lang.NumberFormatException: For input string: "null" when trying to show data in message

Question

I keep coming across this issue, I'm trying to show the date the message has been posted in a messaging application and I keep getting this error and the application keeps crashing.

String message = chatList.get(position).getMessage();
        String timeStamp = chatList.get(position).getTimestamp();

        Calendar cal = Calendar.getInstance(Locale.ENGLISH);
        cal.setTimeInMillis(Long.parseLong(timeStamp));
        String dateTime = DateFormat.format("dd/MM/yyyy hh:mm aa", cal).toString();

        holder.messageTv.setText(message);
        holder.timeTv.setText(dateTime);

This is the logcat error I receive:

2020-09-02 22:10:08.411 13445-13445/com.x00122898.meetupproject E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.x00122898.meetupproject, PID: 13445
    java.lang.NumberFormatException: For input string: "null"
        at java.lang.Long.parseLong(Long.java:594)
        at java.lang.Long.parseLong(Long.java:636)
        at com.x00122898.meetupproject.ChatActivity$1.onDataChange(ChatActivity.java:107)
        at com.google.firebase.database.core.ValueEventRegistration.fireEvent(com.google.firebase:firebase-database@@16.0.4:75)
        at com.google.firebase.database.core.view.DataEvent.fire(com.google.firebase:firebase-database@@16.0.4:63)
        at com.google.firebase.database.core.view.EventRaiser$1.run(com.google.firebase:firebase-database@@16.0.4:55)
        at android.os.Handler.handleCallback(Handler.java:888)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:213)
        at android.app.ActivityThread.main(ActivityThread.java:8178)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1101)
2020-09-02 22:10:08.422 13445-13445/com.x00122898.meetupproject I/Process: Sending signal. PID: 13445 SIG: 9

Any help would be greatly appreciated ~

Timestamp is null. Not normal null, it's the literal string "null". We can't tell why because that code isn't given. — Gabe Sechan
– Gabe Sechan, Commented Sep 2, 2020 at 21:20
You need to post the lines where the timestamp data is being set: chatList.get(position).getTimestamp(). Probably just need to initialize the attribute in the get(position) object. — Boo
– Boo, Commented Sep 2, 2020 at 21:31
For example in the constructor of the object returned from this call chatList.get(position) initialize the timestamp directly :: this.timestamp = String.valueOf(Instant.now().getEpochSecond()); Or maybe initialize it with data from your db or some other way. — Boo
– Boo, Commented Sep 2, 2020 at 21:49

gioramies · Accepted Answer · 2020-09-02 21:37:20Z

0

The problem is in these two lines of code:

String timeStamp = chatList.get(position).getTimestamp();
cal.setTimeInMillis(Long.parseLong(timeStamp));

Your variable timeStamp contains the string/word "null", and when you try to parse it as Long, it throws the NumberFormatException. You must catch the exception or verify if timeStamp contains a numeric value (see How to check if a String is numeric in Java).

Also, maybe the method getTimestamp() is not returning the right variable or the timestamp was never saved or send

answered Sep 2, 2020 at 21:37

gioramies

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marysonthego · Accepted Answer · 2020-09-02 21:44:29Z

0

It looks like the problem occurs at ChatActivity.java line 107 where the value is literally "null". See previous answers numberformatexception-for-input-string-null

answered Sep 2, 2020 at 21:44

marysonthego

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