assertNull(depArtifact.getFile());
        assertFalse(depArtifact.isSnapshot());
        assertEquals("", depArtifact.getClassifier());
        assertEquals("jar", depArtifact.getExtension());
        assertEquals("java", depArtifact.getProperty("language", null));
        assertEquals("jar", depArtifact.getProperty("type", null));
        assertEquals("true", depArtifact.getProperty("constitutesBuildPath", null));

     * The dot separator is not included in the returned string.
     *
     * @return the file extension or an empty string if none, never {@code null}
     */
    @Nonnull
    String getExtension();

    /**
     * {@return a unique string representation identifying this artifact}
     *
     * The default implementation returns a colon-separated list of group

    }

    /**
     * @throws Exception
     */
    public void testGetExtension() throws Exception {
        assertEquals("1", "xml", ResourceUtil.getExtension("aaa/bbb.xml"));
        assertEquals("2", null, ResourceUtil.getExtension("aaa"));
    }

    /**
     * @throws Exception
     */
    public void testRemoteExtension() throws Exception {

                .artifactId(coordinates.getArtifactId())
                .version(coordinates.getVersionConstraint().asString())
                .classifier(coordinates.getClassifier())
                .extension(coordinates.getExtension())
                .build();
    }

    @Nonnull
    static DependencyCoordinatesFactoryRequest build(@Nonnull Session session, @Nonnull Dependency dependency) {
        return builder()

                        result.addException(exception);
                    }
                }
            } else {
                String key = SNAPSHOT + getKey(artifact.getClassifier(), artifact.getExtension());
                merge(infos, SNAPSHOT, key);
                if (!resolve(result, infos, key)) {
                    result.setVersion(version);
                }
            }

            return classifier;
        } else {
            return artifact.getClassifier();
        }
    }

    @Override
    public String getExtension() {
        if (extension != null) {
            return extension;
        } else {
            return artifact.getExtension();
        }
    }

    @Override
    public String getVersion() {
        if (version != null) {
            return version;

    @Nonnull
    Session getSession();

    String getGroupId();

    String getArtifactId();

    String getVersion();

    String getClassifier();

    String getExtension();

    String getType();

    static ArtifactFactoryRequest build(
            Session session, String groupId, String artifactId, String version, String extension) {
        return ArtifactFactoryRequest.builder()

                return session.parseVersionConstraint(dependency.getVersion());
            }

            @Override
            public String getExtension() {
                return getType().getExtension();
            }

            @Override
            public Type getType() {
                String type = dependency.getType();
                return session.requireType(type);

    private String extension, directory, classifier, packaging, language;
    private boolean includesDependencies, addedToClasspath;

    public void setExtension(String extension) {
        this.extension = extension;
    }

    @Override
    public String getExtension() {
        return extension;
    }

    public void setDirectory(String directory) {
        this.directory = directory;
    }

    @Override

    // Implementation
    //

    private File findArtifact(MavenProject project, Artifact artifact, boolean checkUptodate) {
        // POMs are always returned from the file system
        if ("pom".equals(artifact.getExtension())) {
            return project.getFile();
        }

        // Get the matching artifact from the project
        Artifact projectArtifact = findMatchingArtifact(project, artifact);