@Override
  public Class<?> loadClass(String name) throws ClassNotFoundException {
    try {
      return parent.loadClass(name);
    } catch (ClassNotFoundException e) {
      if (useDynamicJars) {
        LOG.debug("Class {} not found - using dynamical class loader", name);
        return tryRefreshClass(name);
      } else if (userConfigUseDynamicJars) {
        // If the user tried to enable the DCL, then warn again.
        LOG.debug("Not checking DynamicClassLoader for missing class because it is disabled."
          + " See the log for previous errors.");
      }
      throw e;
    }
  }
Creates a DynamicClassLoader that can load classes dynamically from jar files under a specific
folder.
@param conf   the configuration for the cluster.
@param parent the parent ClassLoader to set.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/DynamicClassLoader.java