Can we rely on String.isEmpty for checking null condition on a String in Java?

Question

I am passing an accountid as input from an XML file as shown, which will be parsed later and will be used in our code:

123456         


        

Answer 1

No, absolutely not - because if acct is null, it won't even get to isEmpty... it will immediately throw a NullPointerException.

Your test should be:

if (acct != null && !acct.isEmpty())

Note the use of && here, rather than your || in the previous code; also note how in your previous code, your conditions were wrong anyway - even with && you would only have entered the if body if acct was an empty string.

Alternatively, using Guava:

if (!Strings.isNullOrEmpty(acct))