//Before
final ClassLoader loader = new JiveClassLoader(parent, libDir);
Thread.currentThread().setContextClassLoader(loader);
Class sparkClass = loader.loadClass("org.jivesoftware.Spark");
Object instanceOfSpark = sparkClass.newInstance();

//after
final ClassLoader loader = new JiveClassLoader(parent, libDir);
Thread.currentThread().setContextClassLoader(loader);
Class sparkClass = loader.loadClass("org.jivesoftware.Spark");
final Object instanceOfSpark = sparkClass.newInstance();

Because the spark's startup process use a lot time, so add the final to make it faster.

use keyword final to optimize the spark starter

Java