AD0-E137 Adobe Experience Manager Assets Developer Practice Questions

The CRX2Oak tool is a command-line Java utility specifically created by Adobe to migrate content from older CRX2-based AEM versions (AEM 6.2 and earlier) to the new Oak repository structure used in AEM 6.3 and later. It handles the transformation of repository data, version histories, and datastores. It is an essential part of the upgrade process for older AEM instances.

The /cache /rules section determines what is cachable. To prevent caching based on the presence of a request header (like a cookie), you must create a rule that inspects the headers. The configuration /headers { /glob "*login-token*" /type "deny" } instructs the dispatcher to check if any header contains the string login-token. If it does, the /type "deny" directive prevents that request from being cached. This is the correct and secure way to handle authenticated sessions.

The @ScriptVariable annotation allows injection of objects that are typically available in scripting environments like HTL. The currentPage object is one of these standard script variables. By using @ScriptVariable(name="currentPage"), a developer can directly inject the Page object corresponding to the component's context into the Sling Model.

The correct way to handle temporary, recoverable failures in a workflow process step is to use the Granite Workflow API's requeue mechanism. The developer can catch the exception from the external API call, increment a retry counter in the workflow's metadata, and if the retry limit is not exceeded, call workflowSession.requeue(workItem). This puts the item back in the workflow processing queue to be tried again later, without blocking the workflow engine thread. Throwing a WorkflowException will terminate the step, not retry it.

The withMappable HOC from the Adobe SPA libraries is crucial for making a component editable. It injects the necessary authoring attributes and functionality into the React component's DOM.

The Container component from the Adobe library is specifically designed to render the child components of an AEM container. It iterates over the child items in the JSON model and uses the component mapping to render them, while also providing the placeholder for authors to add new components.

The combination of a unique document root for each tenant's site (e.g., /var/www/html/tenantA) and a /statfileslevel that corresponds to the depth of the site structure within that docroot ensures that auto-invalidation via .stat file creation is scoped only to that tenant's directory tree. When content is activated for tenantA, the .stat file is touched only within tenantA's hierarchy, leaving tenantB's cache untouched. Setting /statfileslevel to 0 disables auto-invalidation, which is incorrect. Using /virtualhosts helps with domain mapping but doesn't inherently solve cache invalidation isolation. Unique cache roots are a part of the solution but are ineffective without the correct /statfileslevel and unique docroots.

The AEM standard for managing environment-specific OSGi configurations is to use run mode-specific config folders. By creating config.author and config.publish folders within the project's /apps/my-project/ directory, AEM will automatically apply the correct org.acme.MyService.cfg.json file based on the active run mode of the instance. This approach avoids hardcoding, keeps configuration out of the code, and is the standard deployment practice for AEM projects.

For queries that filter by a specific property value, creating a custom Oak property index is the standard and most efficient solution. By defining an oak:index node (e.g., under /oak:index/acmeTags) with type='property', propertyNames=['acme:tags'], and reindex=true, the Oak repository will build an index that allows for rapid lookups based on that property, drastically improving query performance and avoiding costly repository traversals. Using a Lucene index is more suitable for full-text search. Modifying the query without an index won't solve the underlying traversal issue. Increasing heap size is a temporary fix for memory issues, not slow queries.

The LDAP (Lightweight Directory Access Protocol) Identity Provider is the specific AEM OSGi configuration designed to integrate with directory services like Active Directory. It allows AEM to delegate authentication to the external LDAP server, meaning AEM never stores the passwords. It also supports user and group synchronization, fulfilling the typical requirements for enterprise integration with Active Directory.

Sling Models are the recommended best practice for encapsulating business logic for AEM components. Using a Sling Model allows for clean separation of concerns, moving complex logic out of the presentation layer (HTL). By using annotations like @ChildResource and a @PostConstruct init method, the model can efficiently access JCR data, perform necessary computations, and expose the results through simple getter methods, which can then be easily accessed in HTL. This approach is highly testable, maintainable, and scalable.