Get HTTP ERROR 500 after upgrading basic Flow 24.9.1 app to Flow 25.0.0-alpha12

I created a project using the " * Flow / Java, Maven, and Jetty" option, doing a GitHub clone from GitHub - vaadin/skeleton-starter-flow: Default project template for Vaadin

I slightly modified the POM as shown further down below. I updated version to 24.9.1, and the example app ran successfully.

I changed the package name within the src > main > java folder from org.vaadin to my own package. But otherwise I did not change the content of the app. The same AppShell, GreetService, and MainView classes live there.

So this error should be very easy to replicate.

Changing the POM from <vaadin.version>24.9.1</vaadin.version> to the current <vaadin.version>25.0.0-alpha12</vaadin.version> results in these errors on the console within IntelliJ. Here is an excerpt of the 44K of error messages.

[INFO] Started oejs.Server@565030b7{STARTING}[12.1.1,sto=0] @4938ms
[INFO] Scan interval sec = 2
[vaadin-dev-server-1] INFO com.vaadin.flow.server.frontend.TaskUpdatePackages - using '/Users/basil_dot_work/.vaadin/node/node /Users/basil_dot_work/.vaadin/node/lib/node_modules/npm/bin/npm-cli.js --no-update-notifier --no-audit --scripts-prepend-node-path=true --ignore-scripts install' for frontend package installation
[vaadin-dev-server-1] INFO com.vaadin.flow.server.frontend.TaskUpdatePackages - Frontend dependencies resolved successfully.
[vaadin-dev-server-1] INFO com.vaadin.flow.server.frontend.TaskCopyFrontendFiles - Copying frontend resources from jar files ...
[vaadin-dev-server-1] INFO com.vaadin.flow.server.frontend.TaskCopyFrontendFiles - Visited 21 resources. Took 36 ms.
[vaadin-dev-server-1] INFO com.vaadin.flow.server.frontend.TaskUpdateImports - 

  Failed to find the following imports in the `node_modules` tree:
      - @vaadin/list-box/src/vaadin-list-box.js
      - @vaadin/number-field/src/vaadin-number-field.js
      - @vaadin/grid/src/vaadin-grid-sorter.js
      - @vaadin/multi-select-combo-box/src/vaadin-multi-select-combo-box.js
…
      - @vaadin/accordion/src/vaadin-accordion-panel.js
      - @vaadin/date-time-picker/src/vaadin-date-time-picker.js
      - @vaadin/upload/src/vaadin-upload.js
      - @vaadin/menu-bar/src/vaadin-menu-bar.js
  If the build fails, check that npm packages are installed.

  To fix the build remove `package-lock.json` and `node_modules` directory to reset modules.
  In addition you may run `npm install` to fix `node_modules` tree structure.

[vaadin-dev-server-1] ERROR com.vaadin.flow.server.frontend.TaskRunDevBundleBuild - Command `/Users/basil_dot_work/.vaadin/node/node /Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/vite/bin/vite.js build` failed:
vite v7.1.7 building for production...
transforming...
✓ 2 modules transformed.
vite v7.1.7 building for production...
transforming...
✓ 79 modules transformed.
rendering chunks...
computing gzip size...
../../../target/dev-bundle/webapp/sw.js  71.56 kB │ gzip: 17.60 kB
✓ built in 385ms
✗ Build failed in 1.16s
error during build:
[vite]: Rollup failed to resolve import "@vaadin/vertical-layout/vaadin-vertical-layout.js" from "/Users/basil_dot_work/IdeaProjects/VotersWA/src/main/frontend/generated/vaadin.ts".
This is most likely unintended because it can break your application at runtime.
If you do want to externalize this module explicitly add it to
`build.rollupOptions.external`
    at viteLog (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/vite/dist/node/chunks/dep-Bm2ujbhY.js:33954:57)
    at file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/vite/dist/node/chunks/dep-Bm2ujbhY.js:33990:73
    at Object.onwarn (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/.vite-temp/vite.config.ts.timestamp-1759461137444-b1689d40538028.mjs:1486:11)
    at onwarn (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/@vitejs/plugin-react/dist/index.js:54:78)
    at file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/vite/dist/node/chunks/dep-Bm2ujbhY.js:33990:28
    at onRollupLog (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/vite/dist/node/chunks/dep-Bm2ujbhY.js:33985:63)
    at onLog (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/vite/dist/node/chunks/dep-Bm2ujbhY.js:33786:4)
    at file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/rollup/dist/es/shared/node-entry.js:20936:32
    at Object.logger [as onLog] (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/rollup/dist/es/shared/node-entry.js:22822:9)
    at ModuleLoader.handleInvalidResolvedId (file:///Users/basil_dot_work/IdeaProjects/VotersWA/node_modules/rollup/dist/es/shared/node-entry.js:21566:26)

When pointing my web browser to localhost:8080, I get an 500 error.

HTTP ERROR 500 jakarta.servlet.ServletException: com.vaadin.flow.server.ServiceException: java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status

URI:	http://localhost:8080/
STATUS:	500
MESSAGE:	jakarta.servlet.ServletException: com.vaadin.flow.server.ServiceException: java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status
SERVLET:	com.vaadin.flow.server.startup.ServletDeployer
CAUSED BY:	jakarta.servlet.ServletException: com.vaadin.flow.server.ServiceException: java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status
CAUSED BY:	com.vaadin.flow.server.ServiceException: java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status
CAUSED BY:	java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status
CAUSED BY:	com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status
Caused by:

jakarta.servlet.ServletException: com.vaadin.flow.server.ServiceException: java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Vite build exited with a non zero status
	at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:400)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:723)
	at org.eclipse.jetty.ee11.servlet.ServletHolder.handle(ServletHolder.java:750)
	at org.eclipse.jetty.ee11.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1668)
	at org.eclipse.jetty.ee11.websocket.servlet.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:199)
	at org.eclipse.jetty.ee11.servlet.FilterHolder.doFilter(FilterHolder.java:205)
	at org.eclipse.jetty.ee11.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1640)
	at …
Powered by Jetty:// 12.1.1

My POM:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>project-base</artifactId>
    <name>Project base for Vaadin</name>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <maven.compiler.release>25</maven.compiler.release>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <failOnMissingWebXml>false</failOnMissingWebXml>

        <vaadin.version>25.0.0-alpha12</vaadin.version>
        <drivers.downloader.phase>pre-integration-test</drivers.downloader.phase>
        <jetty.version>12.1.1</jetty.version>
    </properties>

    <repositories>
        <!-- The order of definitions matters. Explicitly defining central here to make sure it has the highest priority. -->
        <repository>
            <id>central</id>
            <url>https://repo.maven.apache.org/maven2</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>vaadin-prereleases</id>
            <url>
                https://maven.vaadin.com/vaadin-prereleases/
            </url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <!-- Repository used by many Vaadin add-ons -->
        <repository>
            <id>Vaadin Directory</id>
            <url>https://maven.vaadin.com/vaadin-addons</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>apache snapshots</id>
            <url>https://repository.apache.org/content/repositories/snapshots</url>
        </repository>
    </repositories>

    <pluginRepositories>
        <!-- The order of definitions matters. Explicitly defining central here to make sure it has the highest priority. -->
        <pluginRepository>
            <id>central</id>
            <url>https://repo.maven.apache.org/maven2</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
        <pluginRepository>
            <id>vaadin-prereleases</id>
            <url>
                https://maven.vaadin.com/vaadin-prereleases/
            </url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-bom</artifactId>
                <type>pom</type>
                <scope>import</scope>
                <version>${vaadin.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>com.vaadin</groupId>
            <!-- Replace artifactId with vaadin-core to use only free components -->
            <artifactId>vaadin</artifactId>
            <!-- Remove the following exclusion if you want to enable Hilla -->
            <exclusions>
                <exclusion>
                    <groupId>com.vaadin</groupId>
                    <artifactId>hilla-dev</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- Added to provide logging output as Vaadin uses -->
        <!-- the unbound SLF4J no-operation (NOP) logger implementation -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
        </dependency>

        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-testbench-junit5</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <defaultGoal>jetty:run</defaultGoal>
        <plugins>
            <!-- Define newer versions of Java compiler and war plugin to better support the latest JDK versions. -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.14.1</version>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.4.0</version>
            </plugin>

            <!-- Jetty plugin for easy testing without a server -->
            <plugin>
                <groupId>org.eclipse.jetty.ee11</groupId>
                <artifactId>jetty-ee11-maven-plugin</artifactId>
                <version>${jetty.version}</version>
                <configuration>
                    <!-- If using IntelliJ IDEA with autocompilation, this
                    might cause lots of unnecessary compilations in the
                    background.-->
                    <scan>2</scan>
                    <!-- Use war output directory to get the webpack files -->
                    <webApp>
                        <allowDuplicateFragmentNames>true</allowDuplicateFragmentNames>
                    </webApp>
                </configuration>
            </plugin>

            <!--
                Take care of synchronizing java dependencies and imports in
                package.json and main.js files.
                It also creates webpack.config.js if not exists yet.
            -->
            <plugin>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-maven-plugin</artifactId>
                <version>${vaadin.version}</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>prepare-frontend</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <profiles>
        <profile>
            <!-- Production mode is activated using -Pproduction -->
            <id>production</id>

            <dependencies>
                <!-- Exclude development dependencies from production -->
                <dependency>
                    <groupId>com.vaadin</groupId>
                    <artifactId>vaadin-core</artifactId>
                    <exclusions>
                        <exclusion>
                            <groupId>com.vaadin</groupId>
                            <artifactId>vaadin-dev</artifactId>
                        </exclusion>
                    </exclusions>
                </dependency>
            </dependencies>
            <build>
                <plugins>
                    <plugin>
                        <groupId>com.vaadin</groupId>
                        <artifactId>vaadin-maven-plugin</artifactId>
                        <version>${vaadin.version}</version>
                        <executions>
                            <execution>
                                <goals>
                                    <goal>build-frontend</goal>
                                </goals>
                                <phase>compile</phase>
                            </execution>
                        </executions>
                    </plugin>
                </plugins>
            </build>
        </profile>

        <profile>
            <id>it</id>
            <build>
                <plugins>
                    <plugin>
                        <groupId>org.eclipse.jetty.ee11</groupId>
                        <artifactId>jetty-ee11-maven-plugin</artifactId>
                        <version>${jetty.version}</version>
                        <configuration>
                            <scan>0</scan>
                            <stopPort>8081</stopPort>
                            <stopWait>5</stopWait>
                            <stopKey>${project.artifactId}</stopKey>
                        </configuration>
                        <executions>
                            <execution>
                                <id>start-jetty</id>
                                <phase>pre-integration-test</phase>
                                <goals>
                                    <goal>start</goal>
                                </goals>
                            </execution>
                            <execution>
                                <id>stop-jetty</id>
                                <phase>post-integration-test</phase>
                                <goals>
                                    <goal>stop</goal>
                                </goals>
                            </execution>
                        </executions>
                    </plugin>

                    <!-- Runs the integration tests (*IT) after the server is started -->
                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-failsafe-plugin</artifactId>
                        <version>3.5.4</version>
                        <executions>
                            <execution>
                                <goals>
                                    <goal>integration-test</goal>
                                    <goal>verify</goal>
                                </goals>
                            </execution>
                        </executions>
                        <configuration>
                            <trimStackTrace>false</trimStackTrace>
                            <enableAssertions>true</enableAssertions>
                        </configuration>
                    </plugin>
                </plugins>
            </build>
        </profile>
    </profiles>
</project>

If I switch the POM back to <vaadin.version>24.9.1</vaadin.version>, the example app runs correctly.

Did the error still occur after deleting package.json, the lock file, node modules and so on?

I did not try any of those actions.

The Vaadin web site had said that migrating a project from 24 to 25 would (hopefully) involve nothing more than a bump in the version number. So that is what I tried, and that clearly does not work (yet).

Leif Åstrand mentioned on a related forum post of mine that the 25 alphas are rough at the moment, with many changes going on. So I will wait for the beta cycle.

Could you try anyways please? If the issues still occur, it might need some additional investigation/work from our side, since that would mean, that there is more than “just” some caching issues and would/could help the product team.