Problem getting Vaadin Flow to work from embedded jetty and Gradle

Flow
1

I am trying to get a small test project to work using embedded jetty, gradle, and Vaadin 14. This is part of our effort to port our vaadin 8 application which already uses embedded jetty.

I took the embeded-jetty-demo from https://github.com/alejandro-du/embedded-jetty-demo.git
and changed it to use gradle instead of maven. See attachment.

When I build and run using embedded jetty and open localhost:8080 I see a directory of files provided by jetty instead of the vaadin app which should show “Does it work?”

  • gradle vaadinPrepareFrontend
  • gradle fatJar
  • java -jar ./build/libs/all-in-one-jar.jar
  • Open http://localhost:8080 in browser and you see a directory of files. What you should see is
    a button which says “Does it work?”

It works if I launch via gjetty gradle plugin which bypasses the embedded jetty code:

  • gradle appRun

As a side note running “gradle vaadinBuildFrontend” never finishes. I have to kill it off after 10-15 minutes. That is perhaps a gradle vaadin plugin bug.

SETUP:

  • OpenJDK 8
  • Gradle 6.3
  • Gradle plugin com.vaadin 0.6.0
  • Jetty 9.4
2

Updated test project attached here.

18241486.zip (71.4 KB)

3

Hi Mike, maybe this example project will be of use https://github.com/mvysny/vaadin14-embedded-jetty-gradle

4

Erik Lumme:
Hi Mike, maybe this example project will be of use https://github.com/mvysny/vaadin14-embedded-jetty-gradle

Thanks Erik! I did not see that example. It sounds perfect except it doesn’t work.

When I clone and run it I get this in the browser window:

Could not navigate to ''
Reason: Couldn't find route for ''
Available routes:
This detailed message is only shown when running in development mode.

So close. So frustrating.

Strangely if I run “gradle run” from CLI it works fine. So something is wrong when I launch from eclipse.

5

I was able to get this to work from Eclipse by adding “build\classes\java\main” to the eclipse launcher classpath.

6

Hi, thank you for posting and I’m happy that you were able to resolve the issue.

The Could not navigate to '' message and the Available routes: message tells you that no @Route-annotated classes have been found on your classpath. You correctly worked around this issue by adding build\classes\java\main to the classpath.

However, the build\classes\java\main path is a standard path for classes output: I wonder whether the issue is actually somewhere in the Eclipse+Buildship direction? I have found a similar issue and a discussion here: https://discuss.gradle.org/t/how-to-add-srcdir-only-for-eclipse-buildship/27007

7

Martin Vyšný:
Hi, thank you for posting and I’m happy that you were able to resolve the issue.

The Could not navigate to '' message and the Available routes: message tells you that no @Route-annotated classes have been found on your classpath. You correctly worked around this issue by adding build\classes\java\main to the classpath.

However, the build\classes\java\main path is a standard path for classes output: I wonder whether the issue is actually somewhere in the Eclipse+Buildship direction? I have found a similar issue and a discussion here: https://discuss.gradle.org/t/how-to-add-srcdir-only-for-eclipse-buildship/27007

That buildship issue does seem like the same thing I encountered.

8

Dear forum,

I have exactly the same problem with Visual Code Studio which is based on BuildShip too.
Could you tell me where I have to add the build\classes\java\main path ?
There’s a configuration to set in the gradle.build file ?

Regards,
Stefano

9

Dear Forum,

I found a solution to this problem and I am now able to use Visual Studio Code with Vaadin, Gradle and a Jetty embedded.
The short answer is that you have to add this configuration in the gradle build file:

eclipse {
    classpath {
        file {
            whenMerged {
                def src = entries.find { it.path == 'src/main/java' }
                src.output = "/$eclipse.project.name/classes/main-java"
            }
        }
    }
}

You could find more information and a complete skeleton project here: [Visual Code Studio @Route error]
(https://github.com/mvysny/vaadin14-embedded-jetty-gradle/issues/4)
For the complete explanation the info are here: [Gradle and Buidship not working for Vaadin project]
(https://discuss.gradle.org/t/gradle-and-buidship-not-working-for-vaadin-project/37463) and here: [Improved Java project synchronization]
(https://discuss.gradle.org/t/buildship-1-0-18-is-now-available/19012)

Regards,
S.