When do forge registries freeze?

I want to initialize things to DeferredRegisters, but not statically.

public static final RegistryObject<Block> bonzanium_casing=register.register(BonzaniumCasing.class.getAnnotation(Register.class).id(),()->new BonzaniumCasing());

↑ This is what I don't want

I want something like this ↓

public static final RegistryObject<Block> bonzanium_casing=register(new BonzaniumCasing());

protected static final RegistryObject<Block> register(Block block){

        if(block.getClass().isAnnotationPresent(Register.class)){
            Register reg = block.getClass().getAnnotation(Register.class);
            String id=reg.id();
            return register.register(id,()->block);
        }else {
            Internal.LOGGER.warn("Block {} has no @Register annotation",block.getClass().getName());
            return null;
        }
    }

Whenever I try to do something like that i get the following error?

Caused by: java.lang.IllegalStateException: Registry is already frozen

Why does that happen? When do the registries freeze?

Edited August 16, 20232 yr by Gogo1234