@Override
    public void close() throws IOException {
        if (closed) { return; }
        this.pluginArtifactZip.close();
        for (ZipFile zipFile : this.dependencyZips) {
            IOUtils.closeQuietly(zipFile);
        }
        closed = true;
    }
Closes any resources the plugin classloader is holding open.
@throws IOException if an I/O error has occurred
common/plugin/src/main/java/io/apiman/common/plugin/PluginClassLoader.java