@Override
    protected synchronized URL findResource(String name) {
        if (notFound.contains(name)) {
            return null;
        }
        try {
            // Send a request to load the resource data
            output.write(ForkServer.RESOURCE);
            output.write(resource);
            output.write(1);
            output.writeUTF(name);
            output.flush();

            // Receive the response
            if (input.readBoolean()) {
                return MemoryURLStreamHandler.createURL(readStream());
            } else {
                notFound.add(name);
                return null;
            }
        } catch (IOException e) {
            return null;
        }
    }
Names of resources that could not be found. Used to avoid repeated
lookup of commonly accessed, but often not present, resources like
<code>META-INF/services/javax.xml.parsers.SAXParserFactory</code>.
tika-core/src/main/java/org/apache/tika/fork/ClassLoaderProxy.java