@Override
    public Map<Long, Window> windowsFor(final long timestamp) {
        throw new UnsupportedOperationException("windowsFor() is not supported by JoinWindows.");
    }
Not supported by {@code JoinWindows}.
Throws {@link UnsupportedOperationException}.

@throws UnsupportedOperationException at every invocation
streams/src/main/java/org/apache/kafka/streams/kstream/JoinWindows.java