No implementation of HttpServerFacade found on classpath

[hasithjp]

Description

This technote should provide an explanation of what to do when you are embedding H2O in your application and after upgrading H2O libraries you start seeing the error

HTTP Server cannot be loaded: No implementation of HttpServerFacade found on classpath
when your application starts.

H2O 3.22.1.1 changed the way dependencies are structured. If your application doesn't directly depend on h2o-app and specifies the individual h2o-modules (h2o-core, h2o-algos, ..) as your dependencies you will not have any implementation of an HTTP Server available and H2O will produce an error.

To fix this issue you can add a dependency to module h2o-jetty-9. If another version of Jetty is present on the classpath, make sure to shadow H2O’s Jetty.

Example (for Gradle):

dependencies {
  compile "ai.h2o:h2o-core:${h2oProjectVersion}"
  compile "ai.h2o:h2o-algos:${h2oProjectVersion}"
  compile "ai.h2o:h2o-genmodel:${h2oProjectVersion}"
  compile "ai.h2o:h2o-web:${h2oProjectVersion}"
  runtime "ai.h2o:h2o-jetty-9:${h2oProjectVersion}"
}

JIRA Issue Migration Info

Jira Issue: TN-13
Assignee: Michal Kurka
Reporter: Michal Kurka
State: Resolved