Identifying a likely cause of a problem in an application can include: injecting a series of a set of predetermined faults into the application; sampling a subset of a set of training features from the application during each predetermined fault injected into the application and labeling each subset with an identifier of the corresponding predetermined fault; and training a classifier to identify the likely cause by associating a set of real-time features sampled from the application that pertain to the problem to one or more of the predetermined faults in response to the training features.