Some fields in a Java array are null, handling of these

Question

I have the following code snippet.

Explanation: I have the array called result. This array consists of different String attributes like "city", "countryName" and "IATA".

With a for loop, I try to access and retrieve all the aforementioned fields.

My problem now is: While "city" and "countryName" always have a value, "IATA" sometimes does not have a value and thus returning me "null", which leads to the nullPointerException as soon as I access an empty "IATA".

I tried this:

if(entry.getIATA().equals(null)) {


                    } else {
                        startIATA[count] = entry.getIATA();
                    }

But, this if condition is not working as I try to access a field which is null. Has anyone an idea how I can solve this?

Here is the relevant code snippet:

private String[] startIATA = new String[200];  //That is more than long enough

...

for (int count = 0; count < result.getAirports().length(); count++) {
                    AirportsEntry entry = result.getAirports().get(count);

                    // Block for StartAirport

                    HorizontalPanel hp = new HorizontalPanel();
                    hp.setSpacing(5);
                    hp.add(new Label(entry.getCity()));
                    hp.add(new Label(entry.getCountryName()));
                    hp.add(new Label(entry.getIATA()));
                    GWT.log("IATA: " + entry.getIATA());

                    if(entry.getIATA().equals(null)) {


                    } else {
                        startIATA[count] = entry.getIATA();
                    }


                    startAirportVP.add(hp);

                }

Thank you very much for your time and your help!

I don't think you can do equal on null can you? Don't you need to do a "==" compare instead. — Martin Larsson
– Martin Larsson, Commented Feb 7, 2013 at 10:22
It is because ".equals" tries to call a method on a object (that's what "." means: call method). But, because your object is null, it errors because you can't call a method on something that doesn't exist. Instead, you can use " == " to check whether the object is null. — David Lavender
– David Lavender, Commented Feb 7, 2013 at 10:22

Kevin Bowersox · Accepted Answer · 2013-02-07 10:20:09Z

3

Perform a simple null check prior to accessing the property of the object.

if(entry != null && entry.getIATA() != null){
    startIATA[count] = entry.getIATA();
}

answered Feb 7, 2013 at 10:20

Kevin Bowersox

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1 Comment

Stefan Badertscher Over a year ago

thank you a lot for this superfast answer! It is working like it should :)

Mikhail Vladimirov · Accepted Answer · 2013-02-07 10:21:51Z

0

You cannot use equals method to check for null. Use ==:

if (entry.getIATA () == null)

answered Feb 7, 2013 at 10:21

Mikhail Vladimirov

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Comments

spiritwalker · Accepted Answer · 2013-02-07 10:24:35Z

0

use this: if (entry.getIATA() != null)

answered Feb 7, 2013 at 10:24

spiritwalker

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