Jetty

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The Maven Jetty plugin runs the app in an embedded Jetty server straight from the project. An archetype project sets compile webforj:watch jetty:run as its default Maven goal, so mvn with no arguments compiles the app, starts the frontend watch, and serves the app on Jetty.

Requirements

A Jetty project declares the development tools itself, in the profile used for development runs:

pom.xml

<profiles>
  <profile>
    <id>dev</id>
    <activation>
      <activeByDefault>true</activeByDefault>
    </activation>
    <dependencies>
      <dependency>
        <groupId>com.webforj</groupId>
        <artifactId>webforj-devtools</artifactId>
      </dependency>
    </dependencies>
  </profile>
</profiles>

The version comes from the webforJ Bill of Materials (BOM). The profile keeps the dependency out of the packaged war. A project created from an archetype has this profile.

Turning live reload on

webforj.conf

webforj.devtools.livereload.enabled = true

The keys are the same ones a Spring Boot app sets in application.properties, listed in the settings.

Class changes

With a hotswap tool configured, the tool applies class changes and Jetty redeploys nothing. Two Jetty properties support this, and an archetype project sets both:

• scan is 0, which turns Jetty's file scanning off.
• deployMode stays unset. Hotswap requires the forked mode, and the plugin selects it. A build that sets deployMode to another value starts without the tool and logs it.

Without a hotswap tool, set scan to an interval in seconds and Jetty redeploys the app when compiled classes or resources change:

Property	Description	Default
scan	Interval in seconds between scans of the compiled output, set as the jetty.scan property. 0 turns scanning off. Longer intervals lower the load and delay the redeploy.	1

Usage considerations

• Memory and CPU: low scan values raise resource consumption on large projects. Longer intervals lower it and delay the redeploy.
• Development only: the Jetty plugin isn't for production deployments.
• Sessions: a redeploy can drop user sessions. A hotswap tool applies changes without a redeploy, and the session survives.