Undertow Concepts

Internal

• Undertow
• XNIO Concepts

Overview

Undertow is a web server written in Java. It provides both blocking and non-blocking APIs based on NIO. It has a composition-based architecture that allows assembling a web server combining small single purpose handlers.

Undertow is embeddable, its lifecycle is controlled by the embedding application and its configuration is controlled programmatically via API calls. Undertow is the default web server in WildFly since version 8, and in this case the configuration is exposed via XML in the server configuration file as:

        ...
        <subsystem xmlns="urn:jboss:domain:undertow:3.0">
            ...
        </subsystem>
        ...

It has support for Servlet 3.1.

Artifacts

• undertow-core
• undertow-servlet provides support for Servlet 3.1
• undertow-websockets-jsr provides support for the Java API for Websockets (JSR-356)

Request Lifecycle

• http://undertow.io/undertow-docs/undertow-docs-1.3.0/index.html#request-lifecycle
• http://undertow.io/undertow-docs/undertow-docs-1.3.0/undertow-request-lifecycle.html

XNIO Concepts

• Worker
• Listener

HttpServerExchange

An exchange can be in blocking or non-blocking mode, and it can be put in blocking mode.