CODEWITHSUNDEEP
javacalendartemboo
user3213348
user3213348

Reputation: 255

why is there a null pointer exception in the for loop, when I can have access the array element?

I am using temboo to get all the events for a calendar. However, i am trying to create a hashtable of the events and the days. but the for loop says its a null pointer exception even though the program is actually able to access that ith element. I have even printed it and the i is less than the size of the array. Here is the snippet code: Error is in the second line of the for loop.Errr occurs when i = 23, but items.size is 41.

GetAllEvents getAllEventsChoreo = new GetAllEvents(session);

// Get an InputSet object for the choreo
GetAllEventsInputSet getAllEventsInputs = getAllEventsChoreo.newInputSet();

// Set inputs
getAllEventsInputs.set_AccessToken(accessToken);
getAllEventsInputs.set_ClientID(clientID);
getAllEventsInputs.set_ClientSecret(clientSecret);
getAllEventsInputs.set_CalendarID(callIDs[0]);

// Execute Choreo
GetAllEventsResultSet getAllEventsResults =    getAllEventsChoreo.execute(getAllEventsInputs);
results = getAllEventsResults.get_Response();
System.out.println(results);

root = jp.parse(results);
rootobj = root.getAsJsonObject();
JsonArray items = rootobj.get("items").getAsJsonArray();

System.out.println("Abour to enter the for loop\nItems:\n"+items.toString());
System.out.println("****************************\nEnter the for loop");
System.out.println("iems Size: "+items.size());
System.out.println(items.get(23).toString());
for(int i = 0;i < items.size();i++)
{
    System.out.println("i: "+i);
    String startTime = items.get(i).getAsJsonObject().get("start").getAsJsonObject().get("dateTime").getAsString();
    System.out.println("startTime: "+startTime);
    String dayKey = startTime.split("T")[0];

    if(dayKey.equals(beginDate)==false | dayKey.equals(endDate)==false)
        {
        System.out.println(startTime + " not the one interested so skipping");
        continue;
        }
    System.out.println("passed the first if in for loop");

    String endTime = items.get(i).getAsJsonObject().get("end").getAsJsonObject().get("dateTime").getAsString();
    String name = items.get(i).getAsJsonObject().get("summary").getAsJsonPrimitive().getAsString();

    calendarEvent eventTemp = new calendarEvent(name,startTime,endTime);

    if(table.containsKey(dayKey))
        table.get(dayKey).add(eventTemp);
    else
    {   
    ArrayList<calendarEvent> schedule = new ArrayList<calendarEvent>();
    schedule.add(eventTemp);
    table.put(dayKey,schedule);
    }
}
Set<String> key = table.keySet();
Iterator<String> it = key.iterator();



    while(it.hasNext())
    {
        String keyValue = it.next();
        System.out.println("Events on "+keyValue);
        ArrayList<calendarEvent> temp = table.get(keyValue);

        for(int j =0;j<temp.size();j++)
        {
            System.out.println(temp.get(j));
        }
    }

After breaking down the exception line, the exception occurs when I try to get the dateTime as string, the last part creates an exception.

Upvotes: 0

Views: 222

Answers (1)

J0e3gan
J0e3gan

Reputation: 8938

Just because the ith element of an array exists, it does not mean that the element is not null.

Referencing a property or method of such an element will yield a NullPointerException.

If i went beyond the bounds of the array, you would get an ArrayIndexOutOfBoundsException instead.

Check indexed array elements for null before using them.

Sorry to be brief and not reference your code or other sources. I am on my phone. The likely source of your problem is pretty clear, though.

Upvotes: 1

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