}
    String oldPathSeparator = PATH_SEPARATOR.value();
    String oldClassPath = JAVA_CLASS_PATH.value();
    System.setProperty(PATH_SEPARATOR.key(), ":");
    System.setProperty(
        JAVA_CLASS_PATH.key(),
        Joiner.on(":")
            .join(
                "relative/path/to/some.jar",
                "/absolute/path/to/some.jar",

    }

    @Override
    public void setProperty(@Nonnull Project project, @Nonnull String key, String value) {
        Properties properties = getMavenProject(project).getProperties();
        if (value == null) {
            properties.remove(key);
        } else {
            properties.setProperty(key, value);
        }
    }

    @Override
    @Nonnull

            }

            project.getModel().addDependency(dependency);
        }

        @Override
        public void afterSessionStart(MavenSession session) {
            session.getUserProperties().setProperty("injected", "bar");
        }
    }

    public static class InjectReactorDependency extends AbstractMavenLifecycleParticipant {
        @Override
        public void afterProjectsRead(MavenSession session) {

        substitute(sp, callback);
        sp.forEach(properties::setProperty);
    }

    public static void substitute(MavenProperties props, UnaryOperator<String> callback) {
        for (Enumeration<?> e = props.propertyNames(); e.hasMoreElements(); ) {
            String name = (String) e.nextElement();
            String value = props.getProperty(name);
            if (value == null) {

    /**
     * {@return an immutable map of the project properties}.
     *
     * @param project the project for which to get the properties
     *
     * @see #setProperty(Project, String, String)
     */
    @Nonnull
    Map<String, String> getProperties(@Nonnull Project project);

    /**
     * Set a given project property. Properties set through this method are only valid

                    .forEach(k -> System.setProperty(k.getKey(), k.getValue()));
        } else {
            protoSession.getUserProperties().entrySet().stream()
                    .filter(k -> context.pushedUserProperties.contains(k.getKey()) || !sys.contains(k.getKey()))
                    .forEach(k -> System.setProperty(k.getKey(), k.getValue()));
        }
    }

    /**

    // cause system property.  This allows us to run with both settings of the property in one jvm
    // without resorting to even crazier hacks to reset static final boolean fields.
    System.setProperty("guava.concurrent.generate_cancellation_cause", "true");
    String concurrentPackage = SettableFuture.class.getPackage().getName();
    classReloader =
        new URLClassLoader(ClassPathUtil.getClassPathUrls()) {

                valueType = getClassForImplementationHint(null, element, loader);
            } catch (final ComponentConfigurationException e) {
                valueType = null;
            }
            helper.setProperty(bean, propertyName, valueType, element);
        }
    }

    /**
     * Clear all caches. Useful for testing or memory management.
     */
    public static void clearCaches() {

        Profile p = Profile.newBuilder().activation(a).build();

        return p;
    }

    private Properties newProperties(String key, String value) {
        Properties props = new Properties();
        props.setProperty(key, value);
        return props;
    }

    @Test
    void testNullSafe() throws Exception {
        Profile p = Profile.newInstance();

        assertActivation(false, p, newContext(null, null));

import org.codehaus.plexus.classworlds.ClassWorld;

import static org.junit.jupiter.api.Assertions.assertEquals;

public abstract class MavenInvokerTestSupport {
    static {
        System.setProperty(
                "library.jline.path",
                Path.of("target/dependency/org/jline/nativ").toAbsolutePath().toString());
    }

    public static final String POM_STRING = """