CMS, Digital Marketing, Java

AEM 6.4 Technical Insights

Adobe’s AEM 6.4 is out and is ready to rock with a set of fantastic and powerful new features as well as key technical upgrades.

The blog will present an overview of key technical changes around Monitoring, Upgrade and component development, that AEM 6.4 is garnished with.

Technical Upgrades/Changes

AEM 6.4 is most awaited release of Adobe’s AEM. With this version Adobe has tried to flavour it with a new technical feature in the backend.

Environmental Changes

Apache jackrabbit Oak: AEM 6.4 uses latest version of Apache Jackrabbit Oak which is 1.8.2. The servlet engine on the backend is upgraded to Eclipse Jetty 9.3.22 which supports HTTP/2 protocol and is targeted and built for Java 8. (Although this still supports java7). Having said that, Java 8 is the recommended version of using AEM6.4. Moreover, AEM 6.4 is built on latest versions of Apache sling and Apache Felix frameworks.

To further add, AEM 6.4 uses dispatcher version 4.2.3 which has significant changes around caching and maven archtype 13 or 13+.

Repository level changes

Although introduced with 6.3, oak segment tar is the core repository level change in terms of storage backend, which has better scalability and faster data storage garbage collection and hence provides better online revision clean-up support.


AEM 6.4 provides better content duplication during compaction. Thanks to the storage level changes as described in the above section. It also introduces two key modes for online revision clean up:

  • Full Compaction
  • Tail Compaction

Also, continuous revision clean-up has replaced the scheduled revision clean-up for MongoMK.


AEM 6.4 has significantly improved the indexing/re-indexing mechanism. The Oak Run tool has been added with a new indexing mode, which you can use to handle almost all indexing use cases, without having to move to JMX. You can re-index your content using this tool. Apart from that this tool gives you out of band support for re-indexing. That means, if you have limitations on your running production environment and you want to re-index, then this tool will allow you to do the same in a cloned environment, to avoid critical performance impact.

Oak run tool also allows you to find out the corrupted index, as well as get the report on the indexing statistics for your further analysis.

Repository Restructuring

Adobe has plans to release updates quarterly for its customers, especially for its managed services ones. To accommodate this, they now want to move away with /etc folder and they have added /conf—a new folder for the configurations. They have also added new mixins to distinguish among Adobe owned, final and extensible nodes.

This new structure will not impact you and your customers immediately as Adobe has decided to still support the legacy nodes, but down the line you may have to relocate your things /etc to the new location.


The new Mixin types are :

  • granite:PublicArea – A node which can be overlaid or inherited
  • granite:FinalArea – A node which should not be overlaid or inherited, but can be used directly
  • granite:InternalArea – A node which should not be overlaid, inherited or used directly


AEM 6.4 upgrades and maintenance overview

AEM Upgrade

With its latest version, AEM gives you an ease of doing upgrade by providing Pattern Detector to assess the complexity you may in upgrading to AEM 6.4. The Pattern Detector can be installed via package manager. Once installed you can get the detailed report of all the deprecated code as well as the node structure that you may consider changing after upgrade.

AEM6.4 also provides you the flexibility for native code development even after the upgrade as it is backward compatible to the AEM’s previous versions. You can run you application in backward compatibility mode and defer the code upgrade for a while. Later, you can analyse the whole code repository to understand where in which place you need to make the changes.


Maintenance & Monitoring

AEM 6.4 has added an extra monitoring layer called System Overview Dashboard in order to get a mountain top view of what is going in your system. The administrators can simply come to this screen and see how everything is working.


Apart from the System Overview Dashboard, a few new sets of health checks have been added around Indexing, Querying and maintenance. For an instance, Large Lucene Indexes check, which uses Lucene Index Statistics MBean to identify the large indexes, has been added to eventually control Lucene binaries churn, with the help of a brand-new Lucene Binaries Maintenance feature. Unlike the previous dependency on the successful data store garbage collection, Lucene binaries can now be cleaned daily basis.


Core Components

Apart from the above changes, AEM 6.4 is also equipped with the version2 of Core Components, which has more ready-to-use components for application development.

Apart from the above technical upgrades, the new version of AEM further simplifies the process of rich website development with many handy tools such as Smart tags, Smart Crop, translated search, Fluid experiences and SPA. With such in built capacities and the flexibility of integrating to other external applications, AEM6.4 can be crowned as the king of CMS systems.

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