使用java流将最后遇到的值放入映射中

I have some code as follows:

我有一些代码如下:

Map<RiskFactor, RiskFactorChannelData> updateMap =
    updates.stream().filter(this::updatedValueIsNotNull). // Remove null updated values
        collect(Collectors.toMap(
            u -> u.getUpdatedValue().getKey(), // then merge into a map of key->value.
            Update::getUpdatedValue,
            (a, b) -> b)); // If two values have the same key then take the second value
Map<