static Object find(String factoryId,
    String fallbackClassName) throws FactoryFinder.ConfigurationError 
{
        dPrint("find factoryId =" + factoryId);
        // Use the system property first
        try {
            String systemProp = ss.getSystemProperty(factoryId);
            if (systemProp != null) {
                dPrint("found system property, value=" + systemProp);
                return newInstance(systemProp, null, true);
            }
        }
        catch (SecurityException se) {
            if (debug) se.printStackTrace();
        }
        // try to read from $java.home/lib/jaxp.properties
        try {
            String factoryClassName = null;
            if (firstTime) {
                synchronized (cacheProps) {
                    if (firstTime) {
                        String configFile = ss.getSystemProperty("java.home") + File.separator +
                            "lib" + File.separator + "jaxp.properties";
                        File f = new File(configFile);
                        firstTime = false;
                        if (ss.doesFileExist(f)) {
                            dPrint("Read properties file "+f);
                            cacheProps.load(ss.getFileInputStream(f));
                        }
                    }
                }
            }
            factoryClassName = cacheProps.getProperty(factoryId);
            if (factoryClassName != null) {
                dPrint("found in $java.home/jaxp.properties, value=" + factoryClassName);
                return newInstance(factoryClassName, null, true);
            }
        }
        catch (Exception ex) {
            if (debug) ex.printStackTrace();
        }
        // Try Jar Service Provider Mechanism
        Object provider = findJarServiceProvider(factoryId);
        if (provider != null) {
            return provider;
        }
        if (fallbackClassName == null) {
            throw new ConfigurationError(
                "Provider for " + factoryId + " cannot be found", null);
        }
        dPrint("loaded from fallback value: " + fallbackClassName);
        return newInstance(fallbackClassName, null, true);
}

Finds the implementation Class object in the specified order. Main entry point.

 static Object newInstance(String className,
    ClassLoader cl,
    boolean doFallback) throws FactoryFinder.ConfigurationError 
{
        try {
            Class providerClass = getProviderClass(className, cl, doFallback);
            Object instance = providerClass.newInstance();
            if (debug) {    // Extra check to avoid computing cl strings
                dPrint("created new instance of " + providerClass +
                       " using ClassLoader: " + cl);
            }
            return instance;
        }
        catch (ClassNotFoundException x) {
            throw new ConfigurationError(
                "Provider " + className + " not found", x);
        }
        catch (Exception x) {
            throw new ConfigurationError(
                "Provider " + className + " could not be instantiated: " + x,
                x);
        }
}

Create an instance of a class. Delegates to method getProviderClass() in order to load the class.