Try with multiple resource causes a sonar qube issue

Question

Please see the code snippet

try (InputStream inputStream = this.getClass().getClassLoader()
                .getResourceAsStream("hello.txt");
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))) {

But sonarQube complaints below error in the above line

Correctness - Nullcheck of value previously dereferenced(line starting with BufferedReader ) .

Please help to resolve this issue

I don't think this is the correct line. The error means that you are doing a null check but already accessed the variable. Can you show more code? — AndiCover, Aug 14 '19 at 10:58
Are you checking for the nullness of `inputStream` anywhere within the try body? — RealSkeptic, Aug 14 '19 at 11:15
I guess, that’s because the code analyzer uses the compiled code and in case of try-with-resource, [it’s a mess](https://stackoverflow.com/a/25746587/2711488), having unreachable code and redundant checks. But if that’s the cause for your problem, the good news is that you get rid of it when updating to JDK 11, even when compiling for `--release 8`. — Holger, Aug 14 '19 at 11:29
By the way, you should use `this.getClass() .getResourceAsStream("/hello.txt")` instead of going through the class loader. This way, the access is compatible with modular software, as a class loader may have multiple modules, but you’re usually referring to the resource with the class’ module. Actually, if you’re not intending to allow resolving to different resources when executed for a subclass, you should use `ActualClassName.class .getResourceAsStream("/hello.txt")`. — Holger, Aug 14 '19 at 11:44

score 2 · Accepted Answer · answered Aug 14 '19 at 12:03

2

It's because getClassLoader().getResourceAsStream("hello.txt") can return null and you're using it just after to create the BufferedReader, without checking for null value.

answered Aug 14 '19 at 12:03

Arnaud Claudel

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So it means, I can't use try with resource in this case rite? – Anoop M Nair Aug 14 '19 at 12:49
Consider using the method [Files.newBufferedReader](https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#newBufferedReader-java.nio.file.Path-) – Arnaud Claudel Aug 14 '19 at 12:57
@ArnaudClaudel The method in `Files` is good for files, not for resources. – RealSkeptic Aug 14 '19 at 13:04
Indeed, so you can just move the `getResourceAsStream` above the `try` and check for null value – Arnaud Claudel Aug 14 '19 at 13:29

Try with multiple resource causes a sonar qube issue

1 Answers1