zap/control/AddOnLoader.java

/*
 * Zed Attack Proxy (ZAP) and its related class files.
 *
 * ZAP is an HTTP/HTTPS proxy for assessing web application security.
 *
 * Copyright 2012 The ZAP Development Team
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.zaproxy.zap.control;

import java.awt.EventQueue;
import java.io.File;
import java.io.FileFilter;
import java.io.FilenameFilter;
import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.ResourceBundle;
import java.util.Set;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.stream.Collectors;
import java.util.zip.ZipEntry;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.FileConfiguration;
import org.apache.commons.configuration.HierarchicalConfiguration;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.parosproxy.paros.Constant;
import org.parosproxy.paros.control.Control;
import org.parosproxy.paros.core.scanner.AbstractPlugin;
import org.parosproxy.paros.extension.Extension;
import org.parosproxy.paros.model.Model;
import org.parosproxy.paros.view.View;
import org.zaproxy.zap.Version;
import org.zaproxy.zap.control.AddOn.AddOnRunRequirements;
import org.zaproxy.zap.control.AddOn.ExtensionRunRequirements;
import org.zaproxy.zap.extension.pscan.PluginPassiveScanner;
import org.zaproxy.zap.utils.ZapXmlConfiguration;

/**
 * This class is heavily based on the original Paros class org.parosproxy.paros.common.DynamicLoader
 * However its been restructured and enhanced to support multiple directories or versioned ZAP
 * addons. The constructor takes an array of directories. All of the generic jars in the directories
 * are loaded. Only the latest ZAP addons are loaded, so if the following addons are found:
 * zap-ext-test-alpha-1.zap zap-ext-test-beta-2.zap zap-ext-test-alpha-3.zap then only the latest
 * one (zap-ext-test-alpha-3.zap) will be loaded - this is entirely based on the version number. The
 * status (alpha/beta/release) is for informational purposes only.
 */
public class AddOnLoader extends URLClassLoader {

    public static final String ADDONS_BLOCK_LIST = "addons.block";

    private static final String ADDONS_RUNNABLE_BASE_KEY = "runnableAddOns";
    private static final String ADDONS_RUNNABLE_KEY = ADDONS_RUNNABLE_BASE_KEY + ".addon";
    private static final String ADDON_RUNNABLE_ID_KEY = "id";
    private static final String ADDON_RUNNABLE_VERSION_KEY = "version";
    private static final String ADDON_RUNNABLE_FULL_VERSION_KEY = "fullversion";
    private static final String ADDON_RUNNABLE_ALL_EXTENSIONS_KEY = "extensions.extension";

    /** A "null" object, for use when no callback is given during the uninstallation process. */
    private static final AddOnUninstallationProgressCallback NULL_CALLBACK =
            new NullUninstallationProgressCallBack();

    private static final Logger logger = LogManager.getLogger(AddOnLoader.class);

    static {
        ClassLoader.registerAsParallelCapable();
    }

    private Lock installationLock = new ReentrantLock();
    private AddOnCollection aoc = null;
    private List<File> jars = new ArrayList<>();
    /**
     * Addons can be included in the ZAP release, in which case the user might not have permissions
     * to delete the files. To support the removal of such addons we just maintain a 'block list' in
     * the configs which is a comma separated list of the addon ids that the user has uninstalled
     */
    private List<String> blockList = new ArrayList<>();

    /**
     * The runnable add-ons and its extensions.
     *
     * <p>The key is the add-on itself and the value its runnable extensions.
     */
    private Map<AddOn, List<String>> runnableAddOns;

    /**
     * The list of add-ons' IDs that have running issues (either the add-on itself or one of its
     * extensions) since last run because of changes in the dependencies.
     */
    private List<String> idsAddOnsWithRunningIssuesSinceLastRun;

    /*
     * Using sub-classloaders means we can unload and reload addons
     */
    private Map<String, AddOnClassLoader> addOnLoaders = new HashMap<>();

    /** File where the data of runnable state and blocked add-ons is saved. */
    private ZapXmlConfiguration addOnsStateConfig;

    public AddOnLoader(File[] dirs) {
        super(new URL[0], AddOnLoader.class.getClassLoader());

        addOnsStateConfig = new ZapXmlConfiguration();
        addOnsStateConfig.setRootElementName("addonsstate");
        File configFile = new File(Constant.getZapHome(), "add-ons-state.xml");
        addOnsStateConfig.setFile(configFile);
        if (!migrateOldAddOnsState(addOnsStateConfig) && configFile.exists()) {
            try {
                addOnsStateConfig.load();
            } catch (ConfigurationException e) {
                logger.warn("Failed to read add-ons' state file:", e);
            }
        }

        this.loadBlockList();

        this.aoc = new AddOnCollection(dirs);
        loadAllAddOns();

        if (dirs != null) {
            for (File dir : dirs) {
                try {
                    this.addDirectory(dir);
                } catch (Exception e) {
                    logger.error(e.getMessage(), e);
                }
            }
        }

        for (File jar : jars) {
            try {
                this.addURL(jar.toURI().toURL());
            } catch (MalformedURLException e) {
                logger.error(e.getMessage(), e);
            }
        }

        // Install any files that are not already present
        for (Entry<String, AddOnClassLoader> entry : addOnLoaders.entrySet()) {
            AddOnInstaller.installMissingAddOnFiles(
                    entry.getValue(), getAddOnCollection().getAddOn(entry.getKey()));
        }
    }

    /**
     * Returns a list with the IDs of add-ons that have running issues since last run, either Java
     * version was changed, or add-on dependencies are no longer met for the add-on or one of its
     * extensions.
     *
     * @return a list with the add-ons that are not longer runnable
     * @since 2.4.0
     */
    public List<String> getIdsAddOnsWithRunningIssuesSinceLastRun() {
        return Collections.unmodifiableList(idsAddOnsWithRunningIssuesSinceLastRun);
    }

    private void loadAllAddOns() {
        for (Iterator<AddOn> iterator = aoc.getAddOns().iterator(); iterator.hasNext(); ) {
            AddOn addOn = iterator.next();
            if (canLoadAddOn(addOn)) {
                AddOnInstaller.installMissingAddOnLibs(addOn);
            } else {
                iterator.remove();
            }
        }

        runnableAddOns = new HashMap<>();
        idsAddOnsWithRunningIssuesSinceLastRun = new ArrayList<>();
        Map<AddOn, AddOnRunState> oldRunnableAddOns = loadAddOnsRunState(addOnsStateConfig, aoc);
        List<AddOn> runAddons = new ArrayList<>();
        Set<AddOn> updatedAddOns = new HashSet<>();
        Set<AddOn> nonRunnableAddOns = new HashSet<>();
        for (Iterator<AddOn> iterator = aoc.getAddOns().iterator(); iterator.hasNext(); ) {
            AddOn addOn = iterator.next();
            AddOnRunRequirements reqs = calculateRunRequirements(addOn, aoc.getAddOns());
            if (reqs.isRunnable()) {
                AddOnRunState runState = oldRunnableAddOns.get(addOn);
                List<String> runnableExtensions;
                if (addOn.hasExtensionsWithDeps()) {
                    runnableExtensions = getRunnableExtensionsWithDeps(reqs);
                    List<String> oldRunnableExtensions =
                            runState != null ? runState.getExtensions() : Collections.emptyList();
                    if (!oldRunnableExtensions.isEmpty()) {
                        oldRunnableExtensions.removeAll(runnableExtensions);
                        if (!oldRunnableExtensions.isEmpty()) {
                            idsAddOnsWithRunningIssuesSinceLastRun.add(addOn.getId());
                        }
                    }
                } else {
                    runnableExtensions = Collections.emptyList();
                }

                runnableAddOns.put(addOn, runnableExtensions);
                runAddons.add(addOn);
                if (runState != null && runState.hasNewerVersion()) {
                    updatedAddOns.add(addOn);
                }
            } else {
                nonRunnableAddOns.add(addOn);
            }
        }

        nonRunnableAddOns.stream()
                .filter(oldRunnableAddOns::containsKey)
                .map(AddOn::getId)
                .forEach(idsAddOnsWithRunningIssuesSinceLastRun::add);

        saveAddOnsRunState(runnableAddOns);

        for (AddOn addOn : runAddons) {
            addOn.setInstallationStatus(AddOn.InstallationStatus.INSTALLED);
            AddOnClassLoader addOnClassLoader = createAndAddAddOnClassLoader(addOn);
            if (updatedAddOns.contains(addOn)) {
                AddOnInstaller.updateAddOnFiles(addOnClassLoader, addOn);
            }
            AddOnInstaller.installResourceBundle(addOnClassLoader, addOn);
        }
    }

    private static List<String> getRunnableExtensionsWithDeps(
            AddOnRunRequirements runRequirements) {
        List<String> runnableExtensions = new ArrayList<>();
        for (ExtensionRunRequirements extReqs : runRequirements.getExtensionRequirements()) {
            if (extReqs.isRunnable()) {
                runnableExtensions.add(extReqs.getClassname());
            }
        }
        return runnableExtensions;
    }

    private boolean canLoadAddOn(AddOn ao) {
        if (blockList.contains(ao.getId())) {
            if (logger.isDebugEnabled()) {
                logger.debug(
                        "Can't load add-on "
                                + ao.getName()
                                + " it's on the block list (add-on uninstalled but the file couldn't be removed).");
            }
            return false;
        }

        if (!ao.canLoadInCurrentVersion()) {
            if (logger.isDebugEnabled()) {
                logger.debug(
                        "Can't load add-on "
                                + ao.getName()
                                + " because of ZAP version constraints; Not before="
                                + ao.getNotBeforeVersion()
                                + " Not from="
                                + ao.getNotFromVersion()
                                + " Current Version="
                                + Constant.PROGRAM_VERSION);
            }
            return false;
        }
        return true;
    }

    private static AddOnRunRequirements calculateRunRequirements(
            AddOn ao, Collection<AddOn> availableAddOns) {
        AddOnRunRequirements reqs = ao.calculateRunRequirements(availableAddOns);
        if (!reqs.isRunnable()) {
            if (logger.isDebugEnabled()) {
                logger.debug(
                        "Can't run add-on "
                                + ao.getName()
                                + " because of missing requirements: "
                                + AddOnRunIssuesUtils.getRunningIssues(reqs));
            }
        }
        return reqs;
    }

    private AddOnClassLoader createAndAddAddOnClassLoader(AddOn ao) {
        try {
            AddOnClassLoader addOnClassLoader = addOnLoaders.get(ao.getId());
            if (addOnClassLoader != null) {
                return addOnClassLoader;
            }

            List<String> idsAddOnDependencies = ao.getIdsAddOnDependencies();
            if (idsAddOnDependencies.isEmpty()) {
                addOnClassLoader =
                        new AddOnClassLoader(
                                ao.getFile().toURI().toURL(), this, ao.getAddOnClassnames());
                putAddOnClassLoader(ao, addOnClassLoader);
                return addOnClassLoader;
            }

            List<AddOnClassLoader> dependencies = new ArrayList<>(idsAddOnDependencies.size());
            for (String addOnId : idsAddOnDependencies) {
                addOnClassLoader = addOnLoaders.get(addOnId);
                if (addOnClassLoader == null) {
                    addOnClassLoader = createAndAddAddOnClassLoader(aoc.getAddOn(addOnId));
                }
                dependencies.add(addOnClassLoader);
            }

            addOnClassLoader =
                    new AddOnClassLoader(
                            ao.getFile().toURI().toURL(),
                            this,
                            dependencies,
                            ao.getAddOnClassnames());
            putAddOnClassLoader(ao, addOnClassLoader);
            return addOnClassLoader;
        } catch (MalformedURLException e) {
            logger.error(e.getMessage(), e);
            throw new RuntimeException(
                    "Failed to convert URL for AddOnClassLoader " + ao.getFile().toURI(), e);
        }
    }

    /**
     * Puts the given add-on class loader into the {@link #addOnLoaders} map and {@link
     * AddOn#setClassLoader(ClassLoader) sets it into the add-on}.
     *
     * <p>The add-on libraries are added to the add-on class loader before that.
     *
     * @param ao the add-on to put in the map.
     * @param addOnClassLoader the class loader of the add-on.
     */
    private void putAddOnClassLoader(AddOn ao, AddOnClassLoader addOnClassLoader) {
        if (!ao.getLibs().isEmpty()) {
            addOnClassLoader.addUrls(
                    ao.getLibs().stream()
                            .map(AddOn.Lib::getFileSystemUrl)
                            .collect(Collectors.toList()));
        }
        ao.setClassLoader(addOnClassLoader);
        addOnLoaders.put(ao.getId(), addOnClassLoader);
    }

    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
        synchronized (getClassLoadingLock(name)) {
            try {
                return loadClass(name, false);
            } catch (ClassNotFoundException e) {
                // Continue for now
            }
            for (AddOnClassLoader loader : addOnLoaders.values()) {
                try {
                    return loader.loadClass(name);
                } catch (ClassNotFoundException e) {
                    // Continue for now
                }
                for (AddOnClassLoader childLoader : loader.getChildClassLoaders()) {
                    try {
                        return childLoader.loadClass(name);
                    } catch (ClassNotFoundException e) {
                        // Continue for now
                    }
                }
            }
            throw new ClassNotFoundException(name);
        }
    }

    @Override
    protected Object getClassLoadingLock(String className) {
        // Allow AddOnClassLoader to use the same locks.
        return super.getClassLoadingLock(className);
    }

    @Override
    public URL getResource(String name) {
        URL url = super.getResource(name);
        if (url != null) {
            return url;
        }
        for (AddOnClassLoader loader : addOnLoaders.values()) {
            url = loader.findResourceInAddOn(name);
            if (url != null) {
                return url;
            }
        }
        return url;
    }

    public AddOnCollection getAddOnCollection() {
        return this.aoc;
    }

    private void addDirectory(File dir) {
        if (dir == null) {
            logger.error("Null directory supplied");
            return;
        }
        if (!dir.exists()) {
            logger.debug("No such directory: " + dir.getAbsolutePath());
            return;
        }
        if (!dir.isDirectory()) {
            logger.warn("Not a directory: " + dir.getAbsolutePath());
            return;
        }

        // Load the jar files
        File[] listJars = dir.listFiles(new JarFilenameFilter());
        if (listJars != null) {
            for (File jar : listJars) {
                this.jars.add(jar);
            }
        }
    }

    public void addAddon(AddOn ao) {
        if (!ao.canLoadInCurrentVersion()) {
            throw new IllegalArgumentException(
                    "Cant load add-on "
                            + ao.getName()
                            + " Not before="
                            + ao.getNotBeforeVersion()
                            + " Not from="
                            + ao.getNotFromVersion()
                            + " Version="
                            + Constant.PROGRAM_VERSION);
        }

        installationLock.lock();
        try {
            if (!this.aoc.addAddOn(ao)) {
                return;
            }

            addAddOnImpl(ao);
        } finally {
            installationLock.unlock();
        }
    }

    private void addAddOnImpl(AddOn ao) {
        if (AddOn.InstallationStatus.INSTALLED == ao.getInstallationStatus()) {
            return;
        }

        if (this.blockList.contains(ao.getId())) {
            // Explicitly being added back, so remove from the block list
            this.blockList.remove(ao.getId());
            this.saveBlockList();
        }

        if (!isDynamicallyInstallable(ao)) {
            return;
        }

        if (!AddOnInstaller.installAddOnLibs(ao)) {
            ao.setInstallationStatus(AddOn.InstallationStatus.NOT_INSTALLED);
            return;
        }

        AddOnRunRequirements reqs = calculateRunRequirements(ao, aoc.getInstalledAddOns());
        if (!reqs.isRunnable()) {
            ao.setInstallationStatus(AddOn.InstallationStatus.NOT_INSTALLED);
            return;
        }

        AddOnInstaller.install(createAndAddAddOnClassLoader(ao), ao);
        ao.setInstallationStatus(AddOn.InstallationStatus.INSTALLED);
        Control.getSingleton().getExtensionLoader().addOnInstalled(ao);

        if (runnableAddOns.get(ao) == null) {
            runnableAddOns.put(ao, getRunnableExtensionsWithDeps(reqs));
            saveAddOnsRunState(runnableAddOns);
        }

        checkAndLoadDependentExtensions();
        checkAndInstallAddOnsNotInstalled();

        if (View.isInitialised()) {
            EventQueue.invokeLater(
                    new Runnable() {

                        @Override
                        public void run() {
                            View.getSingleton().refreshTabViewMenus();
                        }
                    });
        }
    }

    /**
     * Checks and installs all the add-ons whose installation status is {@code NOT_INSTALLED} that
     * have (now) all required dependencies fulfilled.
     *
     * <p>Should be called after an installation of an add-on.
     *
     * @see #addAddOnImpl(AddOn)
     * @see AddOn.InstallationStatus#NOT_INSTALLED
     * @since 2.4.0
     */
    private void checkAndInstallAddOnsNotInstalled() {
        List<AddOn> runnableAddOns = new ArrayList<>();
        for (AddOn addOn : aoc.getAddOns()) {
            if (AddOn.InstallationStatus.NOT_INSTALLED == addOn.getInstallationStatus()
                    && addOnLoaders.get(addOn.getId()) == null) {
                AddOnRunRequirements reqs =
                        addOn.calculateRunRequirements(aoc.getInstalledAddOns());
                if (reqs.isRunnable()) {
                    runnableAddOns.add(addOn);
                }
            }
        }

        for (AddOn addOn : runnableAddOns) {
            addAddOnImpl(addOn);
        }
    }

    /**
     * Checks and loads all the extensions that have (now) all required dependencies fulfilled.
     *
     * <p>Should be called after an installation of an add-on.
     *
     * @see #addAddOnImpl(AddOn)
     * @since 2.4.0
     */
    private void checkAndLoadDependentExtensions() {
        boolean changed = false;
        for (Entry<String, AddOnClassLoader> entry : new HashMap<>(addOnLoaders).entrySet()) {
            AddOn runningAddOn = aoc.getAddOn(entry.getKey());
            if (runningAddOn.getInstallationStatus()
                    == AddOn.InstallationStatus.UNINSTALLATION_FAILED) {
                continue;
            }
            for (String extClassName : runningAddOn.getExtensionsWithDeps()) {
                if (!runningAddOn.isExtensionLoaded(extClassName)) {
                    AddOn.AddOnRunRequirements reqs =
                            runningAddOn.calculateExtensionRunRequirements(
                                    extClassName, aoc.getInstalledAddOns());
                    ExtensionRunRequirements extReqs = reqs.getExtensionRequirements().get(0);
                    if (extReqs.isRunnable()) {
                        List<AddOnClassLoader> dependencies =
                                new ArrayList<>(extReqs.getDependencies().size());
                        for (AddOn addOnDep : extReqs.getDependencies()) {
                            dependencies.add(addOnLoaders.get(addOnDep.getId()));
                        }
                        AddOnClassLoader extAddOnClassLoader =
                                new AddOnClassLoader(
                                        entry.getValue(),
                                        dependencies,
                                        runningAddOn.getExtensionAddOnClassnames(extClassName));
                        Extension ext =
                                loadAddOnExtension(
                                        runningAddOn, extReqs.getClassname(), extAddOnClassLoader);
                        AddOnInstaller.installAddOnExtension(runningAddOn, ext);
                        runnableAddOns.get(runningAddOn).add(extReqs.getClassname());
                        changed = true;
                    }
                }
            }
        }

        if (changed) {
            saveAddOnsRunState(runnableAddOns);
        }
    }

    /**
     * Tells whether or not the given {@code addOn} is dynamically installable.
     *
     * <p>It checks if the given {@code addOn} is dynamically installable by calling the method
     * {@code AddOn#hasZapAddOnEntry()}.
     *
     * @param addOn the add-on that will be checked
     * @return {@code true} if the given add-on is dynamically installable, {@code false} otherwise.
     * @see AddOn#hasZapAddOnEntry()
     * @since 2.3.0
     */
    private static boolean isDynamicallyInstallable(AddOn addOn) {
        return addOn.hasZapAddOnEntry();
    }

    public boolean removeAddOn(
            AddOn ao, boolean upgrading, AddOnUninstallationProgressCallback progressCallback) {
        installationLock.lock();
        try {
            AddOnUninstallationProgressCallback callback =
                    (progressCallback == null) ? NULL_CALLBACK : progressCallback;

            callback.uninstallingAddOn(ao, upgrading);
            boolean removed = removeAddOnImpl(ao, upgrading, callback);
            callback.addOnUninstalled(removed);

            return removed;
        } finally {
            installationLock.unlock();
        }
    }

    private boolean removeAddOnImpl(
            AddOn ao, boolean upgrading, AddOnUninstallationProgressCallback callback) {
        if (!isDynamicallyInstallable(ao)) {
            return false;
        }

        if (AddOn.InstallationStatus.SOFT_UNINSTALLATION_FAILED == ao.getInstallationStatus()) {
            if (runnableAddOns.remove(ao) != null) {
                saveAddOnsRunState(runnableAddOns);
            }
            AddOnInstaller.uninstallAddOnFiles(ao, NULL_CALLBACK, runnableAddOns.keySet());
            removeAddOnClassLoader(ao);
            deleteAddOn(ao, upgrading);
            ao.setInstallationStatus(AddOn.InstallationStatus.UNINSTALLATION_FAILED);
            Control.getSingleton().getExtensionLoader().addOnUninstalled(ao, false);
            return false;
        }

        if (!this.aoc.includesAddOn(ao.getId())) {
            logger.warn("Trying to uninstall an add-on that is not installed: " + ao.getId());
            return false;
        }

        if (AddOn.InstallationStatus.NOT_INSTALLED == ao.getInstallationStatus()) {
            if (runnableAddOns.remove(ao) != null) {
                saveAddOnsRunState(runnableAddOns);
            }

            deleteAddOn(ao, upgrading);

            return this.aoc.removeAddOn(ao);
        }

        unloadDependentExtensions(ao);
        softUninstallDependentAddOns(ao);

        boolean uninstalledWithoutErrors =
                AddOnInstaller.uninstall(ao, callback, runnableAddOns.keySet());

        if (uninstalledWithoutErrors && !this.aoc.removeAddOn(ao)) {
            uninstalledWithoutErrors = false;
        }

        if (uninstalledWithoutErrors) {
            removeAddOnClassLoader(ao);
        }

        deleteAddOn(ao, upgrading);

        if (runnableAddOns.remove(ao) != null) {
            saveAddOnsRunState(runnableAddOns);
        }

        ao.setInstallationStatus(
                uninstalledWithoutErrors
                        ? AddOn.InstallationStatus.AVAILABLE
                        : AddOn.InstallationStatus.UNINSTALLATION_FAILED);

        Control.getSingleton().getExtensionLoader().addOnUninstalled(ao, uninstalledWithoutErrors);
        return uninstalledWithoutErrors;
    }

    /**
     * Deletes the file and libraries of the given add-on.
     *
     * <p>The add-on is added to the {@link #blockList block list} when not able to delete it and if
     * not updating it.
     *
     * @param addOn the add-on to be deleted.
     * @param upgrading {@code true} if the add-on is being updated, {@code false} otherwise.
     * @see AddOnInstaller#uninstallAddOnLibs(AddOn)
     */
    private void deleteAddOn(AddOn addOn, boolean upgrading) {
        AddOnInstaller.uninstallAddOnLibs(addOn);

        if (addOn.getFile() != null && addOn.getFile().exists()) {
            if (!addOn.getFile().delete() && !upgrading) {
                logger.debug("Cant delete " + addOn.getFile().getAbsolutePath());
                this.blockList.add(addOn.getId());
                this.saveBlockList();
            }
        }
    }

    private void removeAddOnClassLoader(AddOn addOn) {
        if (this.addOnLoaders.containsKey(addOn.getId())) {
            try (AddOnClassLoader addOnClassLoader = this.addOnLoaders.remove(addOn.getId())) {
                if (!addOn.getIdsAddOnDependencies().isEmpty()) {
                    addOnClassLoader.clearDependencies();
                }
                ResourceBundle.clearCache(addOnClassLoader);
            } catch (Exception e) {
                logger.error(
                        "Failure while closing class loader of " + addOn.getId() + " add-on:", e);
            }
            addOn.setClassLoader(null);
        }
    }

    private void unloadDependentExtensions(AddOn ao) {
        boolean changed = false;
        for (Entry<String, AddOnClassLoader> entry : new HashMap<>(addOnLoaders).entrySet()) {
            AddOn runningAddOn = aoc.getAddOn(entry.getKey());
            for (Extension ext : runningAddOn.getLoadedExtensionsWithDeps()) {
                if (runningAddOn.dependsOn(ext, ao)) {
                    String classname = ext.getClass().getCanonicalName();
                    AddOnInstaller.uninstallAddOnExtension(runningAddOn, ext, NULL_CALLBACK);
                    try (AddOnClassLoader extensionClassLoader =
                            (AddOnClassLoader) ext.getClass().getClassLoader()) {
                        ext = null;
                        entry.getValue().removeChildClassLoader(extensionClassLoader);
                        extensionClassLoader.clearDependencies();
                        ResourceBundle.clearCache(extensionClassLoader);
                    } catch (Exception e) {
                        logger.error(
                                "Failure while closing class loader of extension '"
                                        + classname
                                        + "':",
                                e);
                    }
                    runnableAddOns.get(runningAddOn).remove(classname);
                    changed = true;
                }
            }
        }

        if (changed) {
            saveAddOnsRunState(runnableAddOns);
        }
    }

    private void softUninstallDependentAddOns(AddOn ao) {
        for (Entry<String, AddOnClassLoader> entry : new HashMap<>(addOnLoaders).entrySet()) {
            AddOn runningAddOn = aoc.getAddOn(entry.getKey());
            if (runningAddOn.dependsOn(ao)) {
                softUninstallDependentAddOns(runningAddOn);

                softUninstall(runningAddOn);
            }
        }
    }

    private void softUninstall(AddOn addOn) {
        if (AddOn.InstallationStatus.INSTALLED != addOn.getInstallationStatus()) {
            return;
        }

        AddOn.InstallationStatus status;
        if (isDynamicallyInstallable(addOn) && AddOnInstaller.softUninstall(addOn, NULL_CALLBACK)) {
            removeAddOnClassLoader(addOn);
            status = AddOn.InstallationStatus.NOT_INSTALLED;
        } else {
            status = AddOn.InstallationStatus.SOFT_UNINSTALLATION_FAILED;
        }

        addOn.setInstallationStatus(status);
        Control.getSingleton()
                .getExtensionLoader()
                .addOnSoftUninstalled(addOn, status == AddOn.InstallationStatus.NOT_INSTALLED);
    }

    private void loadBlockList() {
        blockList = loadList(addOnsStateConfig, ADDONS_BLOCK_LIST);
    }

    private void saveBlockList() {
        saveList(addOnsStateConfig, ADDONS_BLOCK_LIST, this.blockList);
    }

    private <T> List<ClassNameWrapper> getClassNames(String packageName, Class<T> classType) {
        List<ClassNameWrapper> listClassName = new ArrayList<>();

        listClassName.addAll(this.getLocalClassNames(packageName));
        for (String addOnId : this.addOnLoaders.keySet()) {
            listClassName.addAll(this.getJarClassNames(aoc.getAddOn(addOnId), packageName));
        }
        for (File jar : jars) {
            listClassName.addAll(
                    this.getJarClassNames(this.getClass().getClassLoader(), jar, packageName));
        }
        return listClassName;
    }

    /**
     * Returns all the {@code Extension}s of all the installed add-ons.
     *
     * <p>The discovery of {@code Extension}s is done by resorting to the {@link
     * AddOn#MANIFEST_FILE_NAME manifest file} bundled in the add-ons.
     *
     * <p>Extensions with unfulfilled dependencies are not be returned.
     *
     * @return a list containing all {@code Extension}s of all installed add-ons
     * @since 2.4.0
     * @see Extension
     * @see #getExtensions(AddOn)
     */
    public List<Extension> getExtensions() {
        List<Extension> list = new ArrayList<>();
        for (AddOn addOn : getAddOnCollection().getAddOns()) {
            list.addAll(getExtensions(addOn));
        }

        return list;
    }

    /**
     * Returns all {@code Extension}s of the given {@code addOn}.
     *
     * <p>The discovery of {@code Extension}s is done by resorting to {@link
     * AddOn#MANIFEST_FILE_NAME manifest file} bundled in the add-on.
     *
     * <p>Extensions with unfulfilled dependencies are not be returned.
     *
     * <p><strong>Note:</strong> If the add-on is not installed the method returns an empty list.
     *
     * @param addOn the add-on whose extensions will be returned
     * @return a list containing the {@code Extension}s of the given {@code addOn}
     * @since 2.4.0
     * @see Extension
     * @see #getExtensions()
     */
    public List<Extension> getExtensions(AddOn addOn) {
        AddOnClassLoader addOnClassLoader = this.addOnLoaders.get(addOn.getId());
        if (addOnClassLoader == null) {
            return Collections.emptyList();
        }

        List<Extension> extensions = new ArrayList<>();
        extensions.addAll(loadAddOnExtensions(addOn, addOn.getExtensions(), addOnClassLoader));

        if (addOn.hasExtensionsWithDeps()) {
            AddOn.AddOnRunRequirements reqs =
                    addOn.calculateRunRequirements(aoc.getInstalledAddOns());
            for (ExtensionRunRequirements extReqs : reqs.getExtensionRequirements()) {
                if (extReqs.isRunnable()) {
                    List<AddOnClassLoader> dependencies =
                            new ArrayList<>(extReqs.getDependencies().size());
                    for (AddOn addOnDep : extReqs.getDependencies()) {
                        dependencies.add(addOnLoaders.get(addOnDep.getId()));
                    }
                    AddOnClassLoader extAddOnClassLoader =
                            new AddOnClassLoader(
                                    addOnClassLoader,
                                    dependencies,
                                    addOn.getExtensionAddOnClassnames(extReqs.getClassname()));
                    Extension ext =
                            loadAddOnExtension(addOn, extReqs.getClassname(), extAddOnClassLoader);
                    if (ext != null) {
                        extensions.add(ext);
                    }
                } else if (logger.isDebugEnabled()) {
                    logger.debug(
                            "Can't run extension '"
                                    + extReqs.getClassname()
                                    + "' of add-on '"
                                    + addOn.getName()
                                    + "' because of missing requirements: "
                                    + AddOnRunIssuesUtils.getRunningIssues(extReqs));
                }
            }
        }
        return extensions;
    }

    private List<Extension> loadAddOnExtensions(
            AddOn addOn, List<String> extensions, AddOnClassLoader addOnClassLoader) {
        if (extensions == null || extensions.isEmpty()) {
            return Collections.emptyList();
        }

        List<Extension> list = new ArrayList<>(extensions.size());
        for (String extName : extensions) {
            Extension ext = loadAddOnExtension(addOn, extName, addOnClassLoader);
            if (ext != null) {
                list.add(ext);
            }
        }
        return list;
    }

    private static Extension loadAddOnExtension(
            AddOn addOn, String classname, AddOnClassLoader addOnClassLoader) {
        Extension extension =
                AddOnLoaderUtils.loadAndInstantiateClass(
                        addOnClassLoader, classname, Extension.class, "extension");
        if (extension != null) {
            addOn.addLoadedExtension(extension);
        }
        return extension;
    }

    /**
     * Gets the active scan rules of all the loaded add-ons.
     *
     * <p>The discovery of active scan rules is done by resorting to {@link AddOn#MANIFEST_FILE_NAME
     * manifest file} bundled in the add-ons.
     *
     * @return an unmodifiable {@code List} with all the active scan rules, never {@code null}
     * @since 2.4.0
     * @see AbstractPlugin
     */
    public List<AbstractPlugin> getActiveScanRules() {
        ArrayList<AbstractPlugin> list = new ArrayList<>();
        for (AddOn addOn : getAddOnCollection().getAddOns()) {
            AddOnClassLoader addOnClassLoader = this.addOnLoaders.get(addOn.getId());
            if (addOnClassLoader != null) {
                list.addAll(AddOnLoaderUtils.getActiveScanRules(addOn, addOnClassLoader));
            }
        }
        list.trimToSize();
        return Collections.unmodifiableList(list);
    }

    /**
     * Gets the passive scan rules of all the loaded add-ons.
     *
     * <p>The discovery of passive scan rules is done by resorting to {@link
     * AddOn#MANIFEST_FILE_NAME manifest file} bundled in the add-ons.
     *
     * @return an unmodifiable {@code List} with all the passive scan rules, never {@code null}
     * @since 2.4.0
     * @see PluginPassiveScanner
     */
    public List<PluginPassiveScanner> getPassiveScanRules() {
        ArrayList<PluginPassiveScanner> list = new ArrayList<>();
        for (AddOn addOn : getAddOnCollection().getAddOns()) {
            AddOnClassLoader addOnClassLoader = this.addOnLoaders.get(addOn.getId());
            if (addOnClassLoader != null) {
                list.addAll(AddOnLoaderUtils.getPassiveScanRules(addOn, addOnClassLoader));
            }
        }
        list.trimToSize();
        return Collections.unmodifiableList(list);
    }

    /**
     * Gets a list of classes that implement the given type in the given package.
     *
     * <p>It searches in the dependencies, add-ons, and the ZAP JAR.
     *
     * @param packageName the name of the package that the classes must be in.
     * @param classType the type of the classes.
     * @return a list with the classes that implement the given type, never {@code null}.
     * @deprecated (2.8.0) The use of this method is discouraged (specially during ZAP startup, as
     *     it's delayed), it's preferable to provide means to register/declare the required classes
     *     instead of searching "everywhere".
     */
    @Deprecated
    public <T> List<T> getImplementors(String packageName, Class<T> classType) {
        return this.getImplementors(null, packageName, classType);
    }

    /**
     * Gets a list of classes that implement the given type in the given package.
     *
     * <p>It searches in the given add-on, if not {@code null}, otherwise it searches in the
     * dependencies, add-ons, and the ZAP JAR.
     *
     * @param ao the add-on to search in, might be {@code null}.
     * @param packageName the name of the package that the classes must be in.
     * @param classType the type of the classes.
     * @return a list with the classes that implement the given type, never {@code null}.
     * @deprecated (2.8.0) The use of this method is discouraged (specially during ZAP startup, as
     *     it's delayed), it's preferable to provide means to register/declare the required classes
     *     instead of searching "everywhere".
     */
    @Deprecated
    public <T> List<T> getImplementors(AddOn ao, String packageName, Class<T> classType) {
        Class<?> cls = null;
        List<T> listClass = new ArrayList<>();

        List<ClassNameWrapper> classNames;
        if (ao != null) {
            classNames = this.getJarClassNames(ao, packageName);
        } else {
            classNames = this.getClassNames(packageName, classType);
        }
        for (ClassNameWrapper classWrapper : classNames) {
            try {
                cls = classWrapper.getCl().loadClass(classWrapper.getClassName());
                // abstract class or interface cannot be constructed.
                if (Modifier.isAbstract(cls.getModifiers())
                        || Modifier.isInterface(cls.getModifiers())) {
                    continue;
                }
                if (classType.isAssignableFrom(cls)) {
                    @SuppressWarnings("unchecked")
                    Constructor<T> c = (Constructor<T>) cls.getConstructor();
                    listClass.add(c.newInstance());
                }
            } catch (Throwable e) {
                // Often not an error
                logger.debug(e.getMessage(), e);
            }
        }
        return listClass;
    }

    /**
     * Check local jar (zap.jar) or related package if any target file is found.
     *
     * @param packageName the package name that the class must belong too
     * @return a {@code List} with all the classes belonging to the given package
     */
    private List<ClassNameWrapper> getLocalClassNames(String packageName) {

        if (packageName == null || packageName.equals("")) {
            return Collections.emptyList();
        }

        String folder = packageName.replace('.', '/');
        URL local = AddOnLoader.class.getClassLoader().getResource(folder);
        if (local == null) {
            return Collections.emptyList();
        }
        String jarFile = null;
        if (local.getProtocol().equals("jar")) {
            jarFile = local.toString().substring("jar:".length());
            int pos = jarFile.indexOf("!");
            jarFile = jarFile.substring(0, pos);

            try {
                // ZAP: Changed to take into account the package name
                return getJarClassNames(
                        this.getClass().getClassLoader(), new File(new URI(jarFile)), packageName);
            } catch (URISyntaxException e) {
                logger.error(e.getMessage(), e);
            }
        } else {
            try {
                // ZAP: Changed to pass a FileFilter (ClassRecurseDirFileFilter)
                // and to pass the "packageName" with the dots already replaced.
                return parseClassDir(
                        this.getClass().getClassLoader(),
                        new File(new URI(local.toString())),
                        packageName.replace('.', File.separatorChar),
                        new ClassRecurseDirFileFilter(true));
            } catch (URISyntaxException e) {
                logger.error(e.getMessage(), e);
            }
        }
        return Collections.emptyList();
    }

    // ZAP: Changed to use only one FileFilter and the packageName is already
    // passed with the dots replaced.
    private List<ClassNameWrapper> parseClassDir(
            ClassLoader cl, File file, String packageName, FileFilter fileFilter) {
        List<ClassNameWrapper> classNames = new ArrayList<>();
        File[] listFile = file.listFiles(fileFilter);

        for (File entry : listFile) {
            if (entry.isDirectory()) {
                classNames.addAll(parseClassDir(cl, entry, packageName, fileFilter));
                continue;
            }
            String fileName = entry.toString();
            int pos = fileName.indexOf(packageName);
            if (pos > 0) {
                String className =
                        fileName.substring(pos)
                                .replaceAll("\\.class$", "")
                                .replace(File.separatorChar, '.');
                classNames.add(new ClassNameWrapper(cl, className));
            }
        }
        return classNames;
    }

    // ZAP: Added to take into account the package name
    private List<ClassNameWrapper> getJarClassNames(ClassLoader cl, File file, String packageName) {
        List<ClassNameWrapper> classNames = new ArrayList<>();
        ZipEntry entry = null;
        String className = "";
        try (JarFile jarFile = new JarFile(file)) {
            Enumeration<JarEntry> entries = jarFile.entries();
            while (entries.hasMoreElements()) {
                entry = entries.nextElement();
                if (entry.isDirectory() || !entry.getName().endsWith(".class")) {
                    continue;
                }
                className = entry.toString().replaceAll("\\.class$", "").replaceAll("/", ".");
                if (className.indexOf(packageName) >= 0) {
                    classNames.add(new ClassNameWrapper(cl, className));
                }
            }
        } catch (Exception e) {
            logger.error("Failed to open file: " + file.getAbsolutePath(), e);
        }
        return classNames;
    }

    private List<ClassNameWrapper> getJarClassNames(AddOn ao, String packageName) {
        List<ClassNameWrapper> classNames = new ArrayList<>();
        ZipEntry entry = null;
        String className = "";
        try (JarFile jarFile = new JarFile(ao.getFile())) {
            Enumeration<JarEntry> entries = jarFile.entries();
            while (entries.hasMoreElements()) {
                entry = entries.nextElement();
                if (entry.isDirectory() || !entry.getName().endsWith(".class")) {
                    continue;
                }
                className = entry.toString().replaceAll("\\.class$", "").replaceAll("/", ".");
                if (className.indexOf(packageName) >= 0) {
                    classNames.add(
                            new ClassNameWrapper(this.addOnLoaders.get(ao.getId()), className));
                }
            }
        } catch (Exception e) {
            logger.error("Failed to open file: " + ao.getFile().getAbsolutePath(), e);
        }
        return classNames;
    }

    private static final class JarFilenameFilter implements FilenameFilter {
        @Override
        public boolean accept(File dir, String fileName) {
            if (fileName.endsWith(".jar")) {
                return true;
            }
            return false;
        }
    }

    // ZAP: Added
    private static final class ClassRecurseDirFileFilter implements FileFilter {

        private boolean recurse;

        public ClassRecurseDirFileFilter(boolean recurse) {
            this.recurse = recurse;
        }

        @Override
        public boolean accept(File file) {
            if (recurse && file.isDirectory() && !file.getName().startsWith(".")) {
                return true;
            } else if (file.isFile() && file.getName().endsWith(".class")) {
                return true;
            }

            return false;
        }
    }

    private class ClassNameWrapper {
        private ClassLoader cl;
        private String className;

        public ClassNameWrapper(ClassLoader cl, String className) {
            super();
            this.cl = cl;
            this.className = className;
        }

        public ClassLoader getCl() {
            return cl;
        }

        public String getClassName() {
            return className;
        }
    }

    private static List<String> loadList(Configuration config, String key) {
        List<String> data = new ArrayList<>();
        String blockStr = config.getString(key, null);
        if (blockStr != null && blockStr.length() > 0) {
            for (String str : blockStr.split(",")) {
                data.add(str);
            }
        }
        return data;
    }

    private static void saveList(FileConfiguration config, String key, List<String> list) {
        StringBuilder sb = new StringBuilder();

        for (String id : list) {
            if (sb.length() > 0) {
                sb.append(',');
            }
            sb.append(id);
        }

        config.setProperty(key, sb.toString());
        try {
            config.save();
        } catch (ConfigurationException e) {
            logger.error("Failed to save list [" + key + "]: " + sb.toString(), e);
        }
    }

    private static Map<AddOn, AddOnRunState> loadAddOnsRunState(
            HierarchicalConfiguration config, AddOnCollection addOnCollection) {
        List<HierarchicalConfiguration> savedAddOns = config.configurationsAt(ADDONS_RUNNABLE_KEY);

        Map<AddOn, AddOnRunState> runnableAddOns = new HashMap<>();
        for (HierarchicalConfiguration savedAddOn : savedAddOns) {
            AddOn addOn = addOnCollection.getAddOn(savedAddOn.getString(ADDON_RUNNABLE_ID_KEY, ""));
            if (addOn == null) {
                // No longer exists, skip it.
                continue;
            }
            String version = savedAddOn.getString(ADDON_RUNNABLE_FULL_VERSION_KEY, "");
            if (version.isEmpty()) {
                // Try read the old version, which was an integer.
                version = savedAddOn.getString(ADDON_RUNNABLE_VERSION_KEY, "");
            }
            if (version.isEmpty()) {
                // No version, skip it.
                continue;
            }

            int result =
                    addOn.getVersion().compareTo(createLegacyVersion(version, addOn.getName()));
            if (result != 0) {
                if (result > 1) {
                    runnableAddOns.put(addOn, new AddOnRunState());
                }
                // Different version, nothing more to do.
                continue;
            }

            List<String> runnableExtensions = new ArrayList<>();
            List<String> currentExtensions = addOn.getExtensionsWithDeps();
            for (String savedExtension :
                    savedAddOn.getStringArray(ADDON_RUNNABLE_ALL_EXTENSIONS_KEY)) {
                if (currentExtensions.contains(savedExtension)) {
                    runnableExtensions.add(savedExtension);
                }
            }
            runnableAddOns.put(addOn, new AddOnRunState(runnableExtensions));
        }

        return runnableAddOns;
    }

    private static Version createLegacyVersion(String version, String addOnName) {
        try {
            return new Version(version);
        } catch (IllegalArgumentException e) {
            if (logger.isDebugEnabled()) {
                logger.debug(
                        "Failed to create (legacy?) version with ["
                                + version
                                + "] for runnable add-on ["
                                + addOnName
                                + "]",
                        e);
            }
        }

        try {
            return new Version(version + ".0.0");
        } catch (IllegalArgumentException e) {
            if (logger.isDebugEnabled()) {
                logger.debug(
                        "Failed to create legacy version with ["
                                + version
                                + ".0.0] for runnable add-on ["
                                + addOnName
                                + "]",
                        e);
            }
        }

        return null;
    }

    private void saveAddOnsRunState(Map<AddOn, List<String>> runnableAddOns) {
        addOnsStateConfig.clearTree(ADDONS_RUNNABLE_BASE_KEY);

        int i = 0;
        for (Map.Entry<AddOn, List<String>> runnableAddOnEntry : runnableAddOns.entrySet()) {
            String elementBaseKey = ADDONS_RUNNABLE_KEY + "(" + i + ").";
            AddOn addOn = runnableAddOnEntry.getKey();

            addOnsStateConfig.setProperty(elementBaseKey + ADDON_RUNNABLE_ID_KEY, addOn.getId());
            addOnsStateConfig.setProperty(
                    elementBaseKey + ADDON_RUNNABLE_FULL_VERSION_KEY, addOn.getVersion());
            // For older ZAP versions, which can't read the semantic version, just an integer.
            addOnsStateConfig.setProperty(
                    elementBaseKey + ADDON_RUNNABLE_VERSION_KEY,
                    addOn.getVersion().getMajorVersion());

            String extensionBaseKey = elementBaseKey + ADDON_RUNNABLE_ALL_EXTENSIONS_KEY;
            for (String extension : runnableAddOnEntry.getValue()) {
                addOnsStateConfig.addProperty(extensionBaseKey, extension);
            }

            i++;
        }

        try {
            addOnsStateConfig.save();
        } catch (ConfigurationException e) {
            logger.error("Failed to save state of runnable add-ons:", e);
        }
    }

    private static boolean migrateOldAddOnsState(ZapXmlConfiguration newConfig) {
        boolean dataMigrated = false;
        HierarchicalConfiguration oldConfig =
                (HierarchicalConfiguration) Model.getSingleton().getOptionsParam().getConfig();

        if (oldConfig.containsKey(ADDONS_BLOCK_LIST)) {
            List<String> blockList = loadList(oldConfig, ADDONS_BLOCK_LIST);
            oldConfig.clearProperty(ADDONS_BLOCK_LIST);
            saveList(newConfig, ADDONS_BLOCK_LIST, blockList);
            dataMigrated = true;
        }

        List<HierarchicalConfiguration> oldAddOnsState =
                oldConfig.configurationsAt(ADDONS_RUNNABLE_KEY);
        if (!oldAddOnsState.isEmpty()) {
            int i = 0;
            for (HierarchicalConfiguration savedAddOn : oldAddOnsState) {
                String elementBaseKey = ADDONS_RUNNABLE_KEY + "(" + i + ").";
                newConfig.setProperty(
                        elementBaseKey + ADDON_RUNNABLE_ID_KEY,
                        savedAddOn.getString(ADDON_RUNNABLE_ID_KEY, ""));
                String version = savedAddOn.getString(ADDON_RUNNABLE_FULL_VERSION_KEY, "");
                if (version.isEmpty()) {
                    newConfig.setProperty(
                            elementBaseKey + ADDON_RUNNABLE_VERSION_KEY,
                            savedAddOn.getString(ADDON_RUNNABLE_VERSION_KEY, ""));
                } else {
                    newConfig.setProperty(
                            elementBaseKey + ADDON_RUNNABLE_FULL_VERSION_KEY, version);
                }

                String extensionBaseKey = elementBaseKey + ADDON_RUNNABLE_ALL_EXTENSIONS_KEY;
                for (String extension :
                        savedAddOn.getStringArray(ADDON_RUNNABLE_ALL_EXTENSIONS_KEY)) {
                    newConfig.addProperty(extensionBaseKey, extension);
                }
            }
            oldConfig.clearTree(ADDONS_RUNNABLE_KEY);
            dataMigrated = true;
        }
        return dataMigrated;
    }

    /**
     * An {@code UninstallationProgressCallback} that does nothing. A "{@code null}" object, for use
     * when no callback is given during the uninstallation process.
     */
    private static class NullUninstallationProgressCallBack
            implements AddOnUninstallationProgressCallback {

        @Override
        public void uninstallingAddOn(AddOn addOn, boolean updating) {}

        @Override
        public void activeScanRulesWillBeRemoved(int numberOfRules) {}

        @Override
        public void activeScanRuleRemoved(String name) {}

        @Override
        public void passiveScanRulesWillBeRemoved(int numberOfRules) {}

        @Override
        public void passiveScanRuleRemoved(String name) {}

        @Override
        public void filesWillBeRemoved(int numberOfFiles) {}

        @Override
        public void fileRemoved() {}

        @Override
        public void extensionsWillBeRemoved(int numberOfExtensions) {}

        @Override
        public void extensionRemoved(String name) {}

        @Override
        public void addOnUninstalled(boolean uninstalled) {}
    }

    private static class AddOnRunState {

        private final boolean newerVersion;
        private final List<String> extensions;

        public AddOnRunState() {
            this.newerVersion = true;
            this.extensions = Collections.emptyList();
        }

        public AddOnRunState(List<String> extensions) {
            this.newerVersion = false;
            this.extensions = extensions;
        }

        public boolean hasNewerVersion() {
            return newerVersion;
        }

        public List<String> getExtensions() {
            return extensions;
        }
    }
}