return null;
}
try {
final Class<?> foundClass = Class.forName(className);
if (!assignableFrom.isAssignableFrom(foundClass)) {
throw new BadConfigurationException("class " + className + " set in job conf at "
+ configName + " is not a subclass of " + assignableFrom.getCanonicalName());
}
return foundClass;
} catch (ClassNotFoundException e) {
throw new BadConfigurationException("could not instantiate class " + className + " set in job conf at " + configName, e);
}
}