Overview of Mule

Mule is a lightweight Java-based messaging framework that allows you to quickly and easily connect your applications and enable them to exchange data. Mule uses a service-oriented architecture (SOA), enabling easy integration of your existing systems. Regardless of the different technologies the applications use, including JMS, Web Services, JDBC, HTTP, and more, Mule seamlessly handles interactions among them all.

The Mule framework is highly scalable, allowing you to start small and connect more applications over time. Mule manages all the interactions between applications and components transparently, regardless of whether they exist in the same virtual machine or over the Internet, and regardless of the underlying transport protocol used.

Mule is based on ideas from Enterprise Service Bus (ESB) architectures. The key advantage of an ESB is that it allows different applications to communicate with each other by acting as a transit system for carrying data between applications within your intranet or across the Internet. There are currently several commercial ESB implementations on the market. However, many of these provide limited functionality or are built on top of an existing application server or messaging server, locking you into that specific vendor. Mule is vendor-neutral, so different vendor implementations can plug in to it. You are never locked in to a specific vendor when you use Mule.

Advantages of Mule

Mule provides many advantages over competitors, including:

• Mule components can be any type you want. You can easily integrate anything from a "plain old Java object" (POJO) to a component from another framework.
• Mule and the ESB model enable significant component reuse. Unlike other frameworks, Mule allows you to use your existing components without any changes. Components do not require any Mule-specific code to run in Mule, and there is no programmatic API required. The business logic is kept completely separate from the messaging logic.
• Messages can be in any format from SOAP to binary image files. Mule does not force any design constraints on the architect, such as XML messaging or WSDL service contracts.
• You can deploy Mule in a variety of topologies, not just ESB. Because it is lightweight and embeddable, Mule can dramatically decrease time to market and increases productivity for projects to provide secure, scalable applications that are adaptive to change and can scale up or down as needed.

More Information

For a complete overview of Mule, including an introduction to the concepts and architecture, getting started instructions, a glossary, a list of third-party software, and a description of what's new in this release, see the Mule Overview Guide (PDF).