AS7 is the first version of the software to be certified by Oracle as meeting all the specifications of the Java Enterprise Edition 6 (Java EE 6) Web Profile, as determined by passing the tests in the TCK (Technology Compatibility Kit). 

Beyond support for Java EE 6, this release features a number of other updates, most notably a trimming of its computational demands on the server. The start-up time of the program has been cut to around 3 seconds. Also, addressing complaints about all the working memory JBoss can consume, Red Hat has reduced the memory footprint down to 120MB, a reduction of several hundred megabytes. This matches very well JVM Host's 160MB default but upgradeable heap setting for JBoss.

For developers, AS7 implements the open source Arquillian project, which can cut developer testing time by eliminating the need to set up a separate container to run a version of the application being built. It also stores an application's dependent classes so they can be called later without manual intervention from the programmer.

Planned JBoss version 7.1 will be available to JVM Host clients right after release. The 7.1 version should implement, and receive certification for, the entire Java EE 6 stack. Ultimately, JBoss 7.1 will be rolled into the next version of JBoss Enterprise Application Platform (JBoss EAP), which is Red Hat's commercially supported version of JBoss.

Blazingly fast (<3s startup)

Services are started concurrently to eliminate unnecessary waits and leverage multi-core processors, while non-critical services remain passive until first use. JBoss AS 7 offers a 10-fold reduction in startup time over previous versions.

Lightweight

An aggressive approach to memory management and metadata indexing keeps the footprint exceptionally small, enabling it to run with stock JVM settings and on small devices. Profiles can be used to tune the capabilities of the server.

Modular core

JBoss Modules offers true application isolation, hiding server implementation classes and only loads the classes your application needs. Class loading is concurrent for extreme performance. OSGi support is available the moment you install the application server.

Hot, parallel deployment

Quick turnaround during development as a result of fast, concurrent deployment and the ability to edit static resources without redeployment in a flexible deployment structure.

Elegant administration

Consistent and powerful management is available, ranging from a polished, user-friendly web console to Java and HTTP APIs to a command line tool to direct XML edits. Configuration data is centralized and user-focused.

Domain management

JBoss AS 7 can be launched in two different modes. Domain mode allows you to run and manage a multi-server topology. Standalone mode runs a single server instance, a convenience choice for development. Many settings, such as port offsets and network interfaces, can be controlled with a single attribute. Rolling deployments are available.

First class components

JBoss AS builds on many best of breed standalone OSS projects: Hibernate, JBoss Transactions, Infinispan, Iron Jacamar, RESTEasy, Weld, HornetQ, JGroups, JBoss Logging, Mojarra, Apache CXF, and more.

More at JBoss site.