Whats New in AEM 6.0I) Jackrabbit Oak :AEM 6 uses Apache Jackrabbit OAK for it's implementation, an upgrade from CRX2 to CRX 3.

The architecture of Oak was redesigned from scratch to offer improved performance and scalability and support massive content repositories.

As an option MongoDB, a leading NoSQL database, can be used as a persistence layer to support efficiently active/active clustering and user generated content scenarios.

Apart from the changes to the underlying persistence mechanisms, two key high level changes are

MVCC Model : OAK is based on Multiversion Concurrency Control Model. This basically means that whenever a session is dealing with the repository , it will always see snapshot of data what was present when the session started. This is different than Jackrabbit 2 where every session would see the latest version of the repository ( half written data and all ! )No Automatic IndexesWhile Jackrabbit 2 automatically indexed content , OAK does not. This means you have to create your own custom indexes otherwise your searches will be very slow as the whole repository will be traversed. This is pretty much in line with traditional RDBMS technolog.OAK is potentially going to be much more suited to managing transaction type operations in the data/ content than Jackrabbit could ever be .

OAK is the successor of Jackrabbit 2 and is also, based on , JSR 283

Main Components of OAK are Micro Kernel,Oak Core,Oak JCR

Micro Kernel is Based on Strings and leverages JSOP - HTTP Based protocol for working with JSON Objects

Two implementations available in AEM 6 for Micro Kernel - TarMK ( Tar MicroKernel ) and MongoMK

TarMK uses TAR Files , while MongoMK uses MongoDB for storage

MongoDB is adapted to provide sharding and clustering ( Clustering in Mongo is far superior to what was available for CRX in 5.6.1 )

Oak Core - A layer above the MK that adds ACL Controls Search and Indexing Observations ( events )

Oak JCR - A layer that implements the JCR API and helps to translate it into tree operations to affect the Micro Kernel tree structure of content.

Oak does MVCC (Multi-Version Concurrency Control), so periodic garbage collection of revisions (Revision Cleanup) is now a routine (daily) maintenance task.

II) Sightly Templates: Sightly is a JSR 233 compliant scripting language and unlike ESP or JSP, a Sightly template is effectively a valid HTML 5 template, with a couple of key aspects.

DAAS Data Attributes: Specific markup attributes within standard HTML tags.

Sightly Expression Language: Reminiscent of PHP IMHO, consisting of the syntax '$' and ' { } ' which allow you to access node and page properties as well as component context.

Everything else is HTML 5 and any other processing is moved off to a helper class or a code backing class

No more inclusion of init.jsp and global.jsp is needed within the code

III) Coral UI:ExtJS-based Sidekick has been deprecated, in comes a new HTML5, CSS and jQuery-based CoralUI" paradigm with "content frames" and "edit frames", "editables", "layers" (edit layer, preview layer, annotation layer etc.)

While the Classic UI will not disappear suddenly and seems it will be supported for a long time; the majority (if not all) of the newly introduced features leverage the Touch UI.

IV) Technology Stack:The technologies of CQ architectural base has enriched by below updates

Jetty 8 - an extensible, widely used open source web container supporting Servlets 3.0 specification, which has replaced the "own breed" CQSE used previously.

Apache Solr - which can be configured as embedded server or integrated external instance, to replace and extend functionality of default search engine based on Lucene.

New Logback logging framework - external XML config file can be used to configure logging

New (Scene7) Image Server (C++, not Java) for creating dynamic image renditions on demand, in addition to pre-built static image renditions

Sling Health Check Tools-Based on simple HealthCheck OSGi services ,Used to check the health of live Sling systems, based on inputs like JMX MBean attribute values, OSGi framework information, Sling requests status, etc

Sling Resource Merger- To provide services to get "merged" resources, depending either on resource resolver search path or sling:resourceSuperType hierarchy

Forms" : (LiveCycle) Forms, Output, Assembler, Reader Extensions and Digital Signatures leave their J2EE nest and make their debut on the Apache Felix OSGi framework

V) New and Updated features:Social Communities - a collection of redesigned social components based on Social Component Framework which now allow also storage in Adobe Social cloud.

Mobile Apps support - simplifies management and deployment of mobile applications to multiple platforms using PhoneGap Build

Many DAM enhancements - including 2-way syncing with Creative Cloud, Dynamic Media support integrated directly into AEM, processing profiles, metadata schemas, enhanced search and improved team collaboration with projects, workflows and tasks.

Operations Dashboard - allows monitoring and diagnosis of the AEM platform and running maintenance tasks and various health checks, all this from one place

Improved and new integrations with Adobe Marketing Cloud services (including Target and Campaign)

Adaptive Forms - easy-to-use solution to create complex and responsive forms.

VI) obligatory name changes: Sites-formerly Web Content Management (WCM)

Assets-formerly Digital Asset Management (DAM)

AEM Forms Workflow- it was formerly called "LiveCycle Process Management".

Communities- formerly Social Communities (SoCo), for user community discussion forums. Now offers non-JCR cloud storage on Adobe Social (Communities Extension) for scalability