I would like to study mod development for 1.10.2, but I can't find older versions of mods. It may be just a issue of me not knowing how to use github...

Check if the repo has different branches, left side of the page just below the "commits". If you're lucky, there will be different branches for different Minecraft versions. Not all will have this, and not all mods will be on GitHub. Some will be on BitBucket. Others may be in a private repo somewhere. 

As a side note, you should probably go for 1.11.2 at the earliest, and preferably 1.12.x. I don't think 1.10.2 will be supported here for much longer.

The thing is, the demand for 1.7.10 and 1.10.2 exists and it's strong. A huge amount of modded Minecraft player base know their mods because of some Feed The Beast modpack. I want to develop mods that get along well with the famous versions of the famous mods that feature in those insanely popular modpack. And my reason is even more direct: I'll be developing for a server running a custom modpack based upon a FTB mobpack. It's said to hear support for those versions will be dropped.

EDIT: By the way, thank you @lehjr ! found the branches thing and got the code for the release I was looking for,

Edited August 18, 20178 yr by Is.M.L
forgot to thank.

I'm looking at Applied Energistics code (should have picked a different mod, in hindsight) and they import packages they don't have in their code, like this class does:

https://github.com/AppliedEnergistics/Applied-Energistics-2/blob/rv4-1.10/src/main/java/appeng/integration/modules/ic2/IC2Module.java

 

they don't have a package named ic2, how can they be importing ic2.api.recipe.RecipeInputItemStack? Several other classes have similar errors in my eclipse. It should be known that all I did was to copy-paste the java files in the zip I downloaded from the repository into their right locations in my src folder.

Support for 1.7.10 was dropped awhile ago. The issue is that it's simply impossible for Forge and mods to move forward if they are tied up with older versions. And while there is a strong ecosystem for 1.7.10 left for mods, it's also a bad mixture of outdated mods and mods that continually update, sometimes breaking compatibility. If you target a version no longer supported by Forge, then you simply cannot get help here or in the forge IRC channel. It's something to keep in mind if you choose to stick with older versions, that and if you rely on another mod's API, and that API has multiple versions within the same Minecraft version, you're going to have to pick one and deal with the bug reports from that choice alone. 

 

 

4 minutes ago, Is.M.L said:

I'm looking at Applied Energistics code (should have picked a different mod, in hindsight) and they import packages they don't have in their code, like this class does:

https://github.com/AppliedEnergistics/Applied-Energistics-2/blob/rv4-1.10/src/main/java/appeng/integration/modules/ic2/IC2Module.java

 

they don't have a package named ic2, how can they be importing ic2.api.recipe.RecipeInputItemStack? Several other classes have similar errors in my eclipse. It should be known that all I did was to copy-paste the java files in the zip I downloaded from the repository into their right locations in my src folder.

 

Often, the dependencies are handled by Forge Gradle, if they're set up in the mod's config files, otherwise you would have to add them yourself. Applied Energistics is a very sophisticated mod. I'm not sure I would pick that as a starting point. 

Just now, lehjr said:

 

Often, the dependencies are handled by Forge Gradle, if they're set up in the mod's config files, otherwise you would have to add them yourself. Applied Energistics is a very sophisticated mod. I'm not sure I would pick that as a starting point. 

Yeah that was a mistake I realize now. My reasoning was like "what mod is the most popular?" and this is why I decided on AE2. Do you have a suggestion of a better mod to start?

Depends on what you want to do vs what your skill level is. Applied Energistics is a good example of a mod that has multiple API's for the same Minecraft version, but a better example would be something that more closely resembles the mod you want to create.