First, thanks to the author of Rearranger for my favourite IDEA plugin!
I have occasionally had classes that refused to be arranged (usually long legacy code classes, so it was hard to isolate the code that caused the problem). However, now I came across the same behaviour (Rearranger doesn't arrange the class, and throws an exception) and was able to isolate the problem.
Here's a class that Rearranger throws an exception for:
If I change the name of the set method to something else, it works. It also works if I remove the content of the set method. It also works if the set method doesn't have any parameters, or if it has two parameters.
The exception that I get is:
I am using the latest version of Rearranger, and I attached the configuration I'm using. I haven't tried to reproduce the problem with the default configuration.
It seems to be related to parsing getter and setter method names, could be a good idea to also check that methods named 'get' work in all cases.