Converting from raw class type to generic wildcard type

private static <T extends BreweryKeyed> Map<BreweryKey, T> getFields(Class<T> tClass) {
    try {
        ImmutableMap.Builder<BreweryKey, T> outputBuilder = ImmutableMap.builder();
        for (Field field : tClass.getDeclaredFields()) {
            if (!Modifier.isStatic(field.getModifiers())) {
                continue;
            }
            Object staticField = field.get(null);
            if (tClass.isInstance(staticField)) {
                T tInstance = tClass.cast(staticField);
                outputBuilder.put(tInstance.key(), tInstance);
            }
        }
        return outputBuilder.build();
    } catch (IllegalAccessException e) {
        throw new RuntimeException(e);
    }
}

public static final Map<BreweryKey, StructureMeta<?>> STRUCTURE_META = (Map<BreweryKey, StructureMeta<?>>)getFields(StructureMeta.class);