How NPEFix locates bugs?

[Kaka727]

Dear authors,
I read the code of NPEFix and donot find how it processes fault localization.
Does it use an external package or anything else?
Thanks~

[monperrus]

For null pointer exceptions, there is no need for fault localization, the crash point (where the exception is raised) is the number 1 fix point. Methods upper in the crash stack are alternative fix points.