Where are net.minecraft.* packages in the obfuscated version?

[OLEGSHA]

Hello,

I was trying to make a slight change to an obfuscated mod code but my IDE (Eclipse) wouldn't compile without the obfuscated version of the API. I guess I will have to make changes in the deobfuscated src of mod and reobfuscate it but I got curious: when an obfuscated mod addresses stuff like net.minecraft.util.ResourceLocation, where is the corresponding class file located? I searched through .minecraft with forge installed but I could not find any jars that contain net.minecraft package; those classes seem to be named aaa.class, aab.class and so on.

So where is the jar with net.minecraft packages located?

[OLEGSHA]

So does that mean that I cannot edit obfuscated files because no IDE is able to bind to those packages?