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I develop a Java library which is intended for applications based on JDK5. Tools used to build applications require JDK7 or bigger. I use version 8 update 45:

java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)

After the analysis I received a lot of False Positives on methods that are implementing interface specification, e.g:

public interface FileScanner {

    Collection<File> getFiles(File directory, String[] includes, String[] excludes);
}

False Positive Example

(see full sources: https://github.com/gabrysbiz/maven-plugin-utils)

I found that rule makes decisions based on bytecode (see Jira ticket). My class major version is equal to 49 which is related to JDK5 (see major version numbers)

$ javap -verbose AntFileScanner.class
Classfile /D:/Projects/maven-plugin-utils/sources/plugin-utils/target/classes/biz/gabrys/maven/plugin/util/io/AntFileScanner.class
  Last modified 2015-07-16; size 1881 bytes
  MD5 checksum 7ea340377469b44df88d5936c2ff4134
  Compiled from "AntFileScanner.java"
class biz.gabrys.maven.plugin.util.io.AntFileScanner implements biz.gabrys.maven.plugin.util.io.FileScanner
  minor version: 0
  major version: 49
  flags: ACC_SUPER

I run the analysis using Jenkins 1.619 with SonarQube Plugin 2.2.1. I use SonarQube 5.1.1 with Java Plugin 3.4.

How can I correct it?

agabrys
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  • In my opinion this is not a a false positive. An interface in java is nothing more than a special form of a class containing only public abstract methods (since Java 8 even with default implementations). So implementing an interface is a limited form of inheritation (to work around the problems of multiple inheritance), and you in fact override the abstract method. – Uwe Allner Jul 17 '15 at 13:43
  • You didn't understand the question. I have no problem with inheritance, but with [SonarQube](http://www.sonarqube.org/) rule. – agabrys Jul 17 '15 at 14:36
  • I think I did, and I think you perhaps misunderstood the use of @Override annotations. – Uwe Allner Jul 20 '15 at 07:40
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    Override annotation can be applied only to the methods overriding superclass in **JDK5**. Since Java 6 the Override annotation can be applied to methods that implements the interface ones. This means that I can not add annotations in this case. – agabrys Jul 20 '15 at 09:31

2 Answers2

2

Some other people have the same problem, as you can see in the link:

http://blog.gmane.org/gmane.comp.java.sonar.general/page=91

I tried to solve by using the 'sonar.java.source' and 'sonar.java.target' as suggested:

http://docs.sonarqube.org/display/SONAR/Features+details

But I think it only works now for the PMD Plugin:

http://docs.sonarqube.org/display/PLUG/PMD+Plugin

Then, I saw the JIRA ticket. So, actually there is a bug in this situation. The JIRA CR is closed, but the problem still happens on Java 5: https://jira.sonarsource.com/browse/SONARJAVA-249

"In fact we can't implement this rule right now. The @Override annotation has source retention and is removed by the compiler. So our only chance to detect it is from the AST. But, we can detect if a method actually overrides another one only from the bytecode currently. So this rule depends on the symbol table being available from checks."

There is a new unresolved CR to solve this, https://jira.sonarsource.com/browse/SONARJAVA-818.

When fixed, it will use the property 'sonar.java.source' I said before.

So, to solve this while the fix is not ready, we have two options:

1) Mark it as 'false positive' on the server;
2) Use a '@SuppressWarnings' annotation using the rule reference (S1161):

http://docs.sonarqube.org/display/PLUG/Java+FAQ

In this case your code would be:

public class FileScannerImpl implements FileScanner {
    @SuppressWarnings("squid:S1161")
    Collection<File> getFiles(File directory, String[] includes, String[] excludes) {
         [...]
    }
}
Felipe Guimaraes
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1

This was fixed in Java Plugin 3.9 (SONARJAVA-818, see release notes).

agabrys
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