presto-main/src/main/java/io/prestosql/server/PluginClassLoader.java/PluginClassLoader/PluginClassLoader
class PluginClassLoader:    private PluginClassLoader(
            List<URL> urls,
            ClassLoader spiClassLoader,
            Iterable<String> spiPackages,
            Iterable<String> spiResources)
    {
        // plugins should not have access to the system (application) class loader
        super(urls.toArray(new URL[urls.size()]), PLATFORM_CLASS_LOADER);
        this.spiClassLoader = requireNonNull(spiClassLoader, "spiClassLoader is null");
        this.spiPackages = ImmutableList.copyOf(spiPackages);
        this.spiResources = ImmutableList.copyOf(spiResources);
    }