Compare Strings avoiding NullPointerException

Question

When I code I often have to compare two Strings. I know that calling string.equals() throws a java.lang.NullPointerException if the String is null, so what I always do is:

if (string != null && string.equals("something") {
    // Do something
}

This results in having lots of methods that always contains a condition whether a String is null or not.

I would like to avoid this repetition without having an error thrown, is it possible?

score 21 · Accepted Answer · edited May 23 '17 at 12:34

21

Yes, it's possible. Just do:

if ("something".equals(string)) {
    // Do something
}

This will prevent throwing a java.lang.NullPointerException since the Object who calls equals() is not null.

edited May 23 '17 at 12:34

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answered Apr 14 '17 at 10:10

Paolo Forgia

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What if both strings are null? – saumilsdk Aug 28 '20 at 18:03
@saumilsdk It is not possible to call `null.equals(string)`. In case both Strings are a variable you need to call `!= null` on the first one in order to avoid the exception. – Paolo Forgia Sep 07 '20 at 16:09
Is there a better solution using Optional in that case? – saumilsdk Sep 08 '20 at 07:56

Compare Strings avoiding NullPointerException

1 Answers1