Are ConcurrentHashMap changes visible for all threads?

Question

I have CHM as below. I call a method setDataProcessfrom one background thread whenever there is any update. And I always call getDataMappingfrom several streams of readers.

private static final ConcurrentHashMap<ProcessType, Mapping> mappingsHolder = new ConcurrentHashMap<ProcessType, Mapping>();
private static final CountDownLatch hasInitialized = new CountDownLatch(ProcessType.values().length);

public static void setDataProcess(ProcessType processType, Mapping newMapData) {
    mappingsHolder.put(processType, newMapData);
    hasInitialized.countDown();
}

public static Mapping getDataMapping(ProcessType processType) {
    try {
        hasInitialized.await();
        return mappingsHolder.get(processType);
    } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
        throw new IllegalStateException(e);
    }
}

Question: will any change in mappingsHolderCHM be visible to all reader threads instantly, or do I need to use volatile for this?

Answer 1

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Answer 2

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Answer 3

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