I personally have ported about 20K LoC from a java application to go; the majority of the code was from an underlying library used to model the data structures

I personally have ported about 20K LoC from a java application to go; the majority of the code was from an underlying library used to model the data structures being used. It was mostly a class-by-class, function-by-function process of porting the base data structure and then all of its implementations, and culminated with the port of the services which uses all of it. Regarding the author's frustration of moving POJOs over (and their variable declarations), I used sublime text to select all variables based on a shard token, then cut them and moved them over by word. You can then lower case the first letters of every word, and then find-and-replace by type using a shared token. I found this method very quick and effective.