private <T> List<T> fillList(int size, T defaultValue) {
        return new ArrayList<>(Collections.nCopies(size, defaultValue));
    }
most of the features have been delegated to AgentHistogramList upon refactoring
TODO: functionality reduced to creating views - need to be renamed or removed

@author emeroad
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/histogram/AgentTimeHistogram.java