Class JavaPluginLoader

src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java:51–393

Represents a Java plugin loader, allowing plugins in the form of .jar

 * Represents a Java plugin loader, allowing plugins in the form of .jar
 */
public final class JavaPluginLoader implements PluginLoader {
    final Server server;
    private final Pattern[] fileFilters = new Pattern[]{Pattern.compile("\\.jar$")};
    private final Map<String, Class<?>> classes = new ConcurrentHashMap<String, Class<?>>();
    private final List<PluginClassLoader> loaders = new CopyOnWriteArrayList<PluginClassLoader>();
    public static final CustomTimingsHandler pluginParentTimer = new CustomTimingsHandler("** Plugins"); // Spigot

    /**
     * This class was not meant to be constructed explicitly
     *
     * @param instance the server instance
     */
    @Deprecated
    public JavaPluginLoader(@NotNull Server instance) {
        Validate.notNull(instance, "Server cannot be null");
        server = instance;
    }

    @Override
    @NotNull
    public Plugin loadPlugin(@NotNull final File file) throws InvalidPluginException {
        Validate.notNull(file, "File cannot be null");

        if (!file.exists()) {
            throw new InvalidPluginException(new FileNotFoundException(file.getPath() + " does not exist"));
        }

        final PluginDescriptionFile description;
        try {
            description = getPluginDescription(file);
        } catch (InvalidDescriptionException ex) {
            throw new InvalidPluginException(ex);
        }

        final File parentFile = file.getParentFile();
        final File dataFolder = new File(parentFile, description.getName());
        @SuppressWarnings("deprecation")
        final File oldDataFolder = new File(parentFile, description.getRawName());

        // Found old data folder
        if (dataFolder.equals(oldDataFolder)) {
            // They are equal -- nothing needs to be done!
        } else if (dataFolder.isDirectory() && oldDataFolder.isDirectory()) {
            server.getLogger().warning(String.format(
                "While loading %s (%s) found old-data folder: `%s' next to the new one `%s'",
                description.getFullName(),
                file,
                oldDataFolder,
                dataFolder
            ));
        } else if (oldDataFolder.isDirectory() && !dataFolder.exists()) {
            if (!oldDataFolder.renameTo(dataFolder)) {
                throw new InvalidPluginException("Unable to rename old data folder: `" + oldDataFolder + "' to: `" + dataFolder + "'");
            }
            server.getLogger().log(Level.INFO, String.format(
                "While loading %s (%s) renamed data folder: `%s' to `%s'",
                description.getFullName(),
                file,