I am wanting to add support for other mods within my mod by using other mod's APIs, but I don't want my mod to depend on having these other mods installed, so if Mod 1 wasn't installed, Mod 2 was, the support would be there for Mod 2 still. Is there a way to do this?

Your question is a bit two-sided when it comes to what you mean.

How to check if a mod is loaded?

if(Loader.isModLoaded("other_mod's_modid"))
//do stuff with things from this mod.

 

How to get rid of dependency, but still make use of X.

Dependency is the easiest and most stable way of getting cross-mod interactions. That has to be said.

However, for simple things like entities, items, blocks etc, they can all be accessed from strings (Item.getByNameOrId(modid:name), Block.getBlockFromName(modid:name) and EntityList.NAME_TO_CLASS.get(name)) though they should always have null checks, case their name changes or they are, as mentioned, not installed together with your mod.

 

However, for full and complete freedom from dependencies, you want to learn about java reflection, and find classes from strings, instantiate them from scratch, which would be very prone to complete failure should a single thing change in a constructor.

 

It's a long and twisted road to go down if you are not quite adapt with Java. You sure you want to go down it?

Thanks, that clears everything up that I wanted to know, whether you fully understood what I was trying to say anyway For the most part I will just be using other mod's blocks/items so what you said will work fine, but then if there is any other classes I need then I might as well learn reflection at some point, but it most likely won't be necessary for what I want to do.

 

Thanks again