Some methods of PropertiesDepot return null rather than throw exceptions. Some calls to these methods do not check for null. For example, traverseConfigurationFile() calls getConfigurationFile(). If getConfigurationFile() fails, traverseConfigurationFile() issues NullPointerException, not a very useful message for users.
Null checks can be added as a fix. IMO a better solution is not to trap the exceptions in utility classes like PropertiesDepot. The null check amounts to a one-bit return code: we need to check it on every call at every level but once we get back to UI code all we know is "failed".