code: private void configureAdditionalClasspath(final ClassRealm realm) {
      log.debug("Configuring additional classpath with scope: {}", classpathScope);
  
      List<File> classpath = Lists.newArrayList();
  
      // add build output directory if scope includes 'compile'
      if (classpathScope.matches(compile)) {
        classpath.add(new File(project.getBuild().getOutputDirectory()));
      }
  
      // add build test output directory if scope includes 'test'
      if (classpathScope.matches(test)) {
        classpath.add(new File(project.getBuild().getTestOutputDirectory()));
      }
  
      // add matching project dependency artifacts
      if (!project.getArtifacts().isEmpty()) {
        for (Artifact artifact : project.getArtifacts()) {
          if (classpathScope.matches(artifact.getScope())) {
            File file = artifact.getFile();
            if (!file.exists()) {
              // for sanity, this should not really ever happen
              log.warn("Artifact not resolved; ignoring: {}", artifact);
              continue;
            }
            classpath.add(file);
          }
        }
      }
  
      if (!classpath.isEmpty()) {
        log.debug("Additional classpath:");
        for (File file : classpath) {
          log.debug("  {}", file);
          try {
            realm.addURL(file.toURI().toURL());
          }
          catch (MalformedURLException e) {
            throw Throwables.propagate(e);
          }
        }
      }
    }
docs: Configure additional classpath elements for the runtime realm.