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Live Reload

The Jetty Maven plugin with the scanIntervalSeconds configuration set to a positive value performs complete application restart when the given number of seconds have elapsed since the last Java change. For instance:

<plugins>
    <plugin>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-maven-plugin</artifactId>
        <version>9.4.36.v20210114</version>
        <configuration>
            <scanIntervalSeconds>2</scanIntervalSeconds>
        </configuration>
    </plugin>

    <!-- more plugins -->
</plugins>
Note
Recommended minimum version

Jetty Maven Plugin versions before 9.4.36.v20210114 have known issues:

  • RouteNotFoundException when trying to reload Java changes automatically

  • A reload loop on Windows when setting scanIntervalSeconds to a small positive value

Since the plugin performs a full server restart, all Java changes are picked up. This includes modifications to server startup listeners, as well as changes to code that connects front-end and back-end components, such as adding a new LitTemplate class, or adding a new CSS import and using it in Java via the @CssImport annotation.

However, the session isn’t preserved during the restart.

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