SonarQube plugin with set of rules detecting possible bugs and bad smells specific for AEM development.
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chutch Merge pull request #118 from Cognifide/issue-112
fixes #112 - HTL Templates should be placed in separate files
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About AEM Rules for SonarQube

AEM Rules for SonarQube


As we all know, SonarQube is a great tool that helps us increase quality of our codebase. However, it does apply mainly to general Java issues. As we know, we can hurt ourselves much more doing AEM. Adobe Experience Manager is a comprehensive content management platform solution for building websites, mobile apps and forms. This tool is intended to find common bugs and bad smells specific for AEM development. Documentation of each rule is available from SonarQube interface after plugin installation.


Each release has its own prerequisites section, for more information please check releases page.


Update Center

Go to your SonarQube instance administration console and open Update Center. Find AEM Rules for SonarQube plugin and click install!


  1. Download aemrules-x.y.jar or build AEM Rules for SonarQube plugin.
  2. Paste it into sonarqube/extensions/plugins directory.
  3. Restart SonarQube.
  4. Go to rules section and activate AEM rules in your profile.


Use of the plugin does not differ much from regular SonarQube analysis. However, as rules are often tied to a certain AEM version and its components (Felix, Sling), we've introduced the aemVersion analysis property.

Each rule defines supported AEM version or version range. Most of the rules are universal. By providing the AEM version parameter, you can instruct the Sonar Runner to only use only a subset of rules applicable to a particular AEM version. When the parameter is not provided then a default AEM version is used (currently 6.4)

Running analysis

When running analysis, pass sonarRunner.aemVersion property with your AEM version. The format is as follows:


Runing with Maven

mvn sonar:sonar -DsonarRunner.aemVersion=6.4

Runing with Gradle (See Gradle AEM Plugin)

gradlew sonarQube -DsonarRunner.aemVersion=6.4

Rule set

Below you will find descriptions of all rules available in AEM Rules for SonarQube plugin.

Good practices

  • AEM-1 Use predefined constant in annotation instead of hardcoded value.

    • Use constants available in AEM instead of repeating inline literals.
  • AEM-2 Use predefined constant instead of hardcoded value.

    • Use constants available in AEM instead of repeating inline literals.
  • AEM-8 Prefer cleaner @SlingServlet annotation.

    • Prefer cleaner @SlingServlet annotation over @Properties approach. Do not mix up both approaches.
  • AEM-14 Using http literal hardcoded makes it difficult to switch to https later on.

    • We should not use http as a literal in our projects because if we want to switch to https, our code will be not ready.
  • AEM-15 Usage of synchronized keyword should be avoided if possible.

    • Usage of synchronized keyword should be avoided if possible. Check if using synchronized can be replaced with more sophisticated solution.
  • AEM-17 No mutator methods invoked on ModifiableValueMap

    • ModifiableValueMap should be replaced by ValueMap if no mutator methods are invoked.
  • AEM-19 Implicit search strategy used in Sling Query

    • SearchStrategy can have negative performance impact if mismatched. Therefore developer should always make informed decision and define strategy explicitly.

Possible bugs

  • AEM-3 Non-thread safe object used as a field of Servlet / Filter etc.

    • It is not safe to keep session based object as a field in Servlet or Filter. Rule checks for the occurrence of any instance or static fields of following types:
      • javax.jcr.Session
  • AEM-6 ResourceResolver should be closed in finally block.

    • According to its Javadoc, Resource Resolver has a life cycle which begins with the creation of the Resource Resolver using any of the factory methods and ends with calling the close method. It is very important to call the close method once the resource resolver is not used any more to ensure any system resources are properly clean up.
  • AEM-7 Session should be logged out in finally block.

    • Manually created javax.jcr.Session should be logged out after it is no longer needed. The logout method releases all resources associated with Session.
  • AEM-11 Do not use deprecated administrative access methods

    • Administrative access to the resource tree and JCR Repository by means of usage of ResourceResolverFactory.getAdministrativeResourceResolver and SlingRepository.loginAdministrative has been deprecated. Use ResourceResolverFactory.getServiceResourceResolver or SlingRepository.loginService respectively.

Slice related

  • AEM-4 Injector should be closed in finally block or created as a resource within try block.

    • Injectors (com.cognifide.slice.api.injector.InjectorWithContext) are created in the context of either request or resource resolver. To restore its initial state after using injector, it should be closed in finally block or created as a resource within try block.
  • AEM-5 Injector can be closed using try-with-resources Java 7 feature.

    • Take advantage of Java 7 try-with-resources feature to close com.cognifide.slice.api.injector.InjectorWithContext.
  • AEM-9 Objects annotated by @SliceResource should not use (except: constructor, com.cognifide.slice.api.model.InitializableModel.afterCreated()) and return any session based object.

    • Objects annotated by @SliceResource should not use any session based objects, except places like constructor and overridden com.cognifide.slice.api.model.InitializableModel.afterCreated() method.
  • AEM-10 Use ModelProvider#getListFromResources instead of iteration

    • Slice provides method for creating list of models from specified resources given as an Iterator. Instead of iterating over resources yourself, use ModelProvider#getListFromResources method.
  • AEM-12 Fields annotated by @JcrProperty shouldn't be accessed from constructor.

    • Fields that are annotated with @JcrProperty should not be accessed from within constructor.

Sling Models related

  • AEM-16 Optional is defined as DefaultInjectionStrategy
    • Usage of @Optional annotation is redundant, when defaultInjectionStrategy is OPTIONAL.

Release notes

Release notes for each version can be found in releases section.


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