Examples

(You can also look at my mod Lifed for more)
A simple config that will store one int with a comment above it

import z3roco01.composed.annotation.*;

public class ExampleConfig {
    @Comment(comment = "should we kill them all")
    @ConfigProperty
    public boolean killEveryone = true;
}

To then load and save the config:

import z3roco01.composed.file.ConfigFile;

public class ModMain implements ModInitializer {
    public static final ExampleConfig config = new ExampleConfig();
    
    @Override
    public void onInitialize() {
        // need to catch exceptions that load and store can produce
        try {
            // load in the values or store defaults
            ConfigFile.load("./config/example.conf", config);
        }catch(IOException | IllegalAccessException e) {
            throw new RuntimeException(e);
        }
        
        // do stuff with the config values
        if(config.killPlayers) {
            killEveryone();
        }
    }
}

The config file .minecraft/config/example.conf will look like:

# should we kill them all
killEveryon=true