You mean that you have opened the class file, and saw the actual source code? Class file is supposed to be object-code (or whatever java calls that) - which can be decompiled (and sometimes even in a meaningful way), but generally it is not supposed to be the source itself...
(I just downloaded goland, and extracted a random jar file, and at least with that, the above paragraph seems to stand)
(I just downloaded goland, and extracted a random jar file, and at least with that, the above paragraph seems to stand)