- plugin execution error due to something that is not expected to go wrong (the compiler executable missing)
- asking to use a plugin for which you do not have a version defined - tools to easily select versions
- goal not found in a plugin (probably could list the ones that are)

 */

// PluginNotFoundException, PluginResolutionException, PluginDescriptorParsingException,

                List<String> exports = exportedPackages.get(extensionRealm);

                if (exports == null || exports.isEmpty()) {
                    /*
                     * Most existing extensions don't define exported packages, i.e. no classes are to be exposed to
                     * plugins, yet the components provided by the extension (e.g. artifact handlers) must be

                     * happens, add on class-path or module-path if allowed, or keep patching otherwise.
                     * The latter case (keep patching) is okay if the main module will be defined later.
                     */
                    type = cache.selectPathType(pathTypes, filter, path).orElse(type);
                }
                addPathElement(type, info.getKey());

META-INF/LICENSE.txt Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. Definitions. "License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document. "Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License. "Legal Entity" shall mean the union of the acting entity and all other entities that control,...

with a property named org.apache.commons.logging.LogFactory defining the desired implementation class name. Fall back to a default implementation, which is described further below. If a commons-logging.properties file is found, all of the properties defined there are also used to set configuration attributes on the instantiated LogFactory instance. Once an implementation class name is selected, the corresponding class is loaded from the current Thread context class loader (if there is one), or from the...

                                </requireJavaVersion>
                                <requireNoRepositories>
                                    <message>Best Practice is to never define repositories in pom.xml (use a repository
                                        manager instead).
                                    </message>
                                </requireNoRepositories>

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

     *
     * @param child The child model, must not be <code>null</code>.
     * @param parent The parent model, may be <code>null</code>.
     * @param childDirectory The directory defined in child model, may be <code>null</code>.
     * @return The path adjustment, can be empty but never <code>null</code>.
     */
    private String getChildPathAdjustment(Model child, Model parent, String childDirectory) {

   | value of '1.4' might activate a profile when the build is executed on a JDK version of '1.4.2_07'.
   | Finally, the list of active profiles can be specified directly from the command line.
   |
   | NOTE: For profiles defined in the settings.xml, you are restricted to specifying only artifact
   |       repositories, plugin repositories, and free-form properties to be used as configuration
   |       variables for plugins in the POM.
   |
   |-->

                     * happens, add on class-path or module-path if allowed, or keep patching otherwise.
                     * The latter case (keep patching) is okay if the main module will be defined later.
                     */
                    type = cache.selectPathType(pathTypes, filter, path).orElse(type);
                }
                addPathElement(type, info.getKey());