CODEWITHSUNDEEP
springspring-bootfindbugs
Ronnie J
Ronnie J

Reputation: 31

spring 2.0 findbugs nullable throws error even when wrapped in null check

I'm having difficulty with Findbugs complaining about springs HttpEntity.getBody().

Below you'll see I call response.getBody().length, which I understand could cause a NPE. However when I wrap it in if (response.getBody() != null), it still complains. It only does this in Spring 2.0 (not 1.5) which appears to be related to the @Nullable annotation added to the method.

Can I get an explanation why even when I wrap it in a null check, it still complains when I get the length of it?

Bug type NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE 

ResponseEntity<SomeClass[]> response = restTemplate.exchange(someUrl, HttpMethod.GET, httpEntity,
                SomeClass[].class);
for (int i = 0; response.getBody().length > i;   i++) {
                        doSomething()
                    }

Upvotes: 3

Views: 935

Answers (1)

Ugo Uchegbu
Ugo Uchegbu

Reputation: 141

According to Spot bugs documentation the reason for this occuring is :

'The return value from a method is dereferenced without a null check, and the return value of that method is one that should generally be checked for null. This may lead to a NullPointerException when the code is executed.'

fixed it by: 

Optional <T> body = Optional.ofNullable(response.getBody);
if (body.isPresent()) {
   //use body
}

You are getting the warning because getBody method has been annotated as Nullable and spotBugs / findbugz expects that an explicit null checker be made before using the value. Works well for me.

Upvotes: 1

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