@Override
    public void clear() {
        cacheManager.getCaches().forEach((name, cache) -> {
            LOGGER.debug("Clearing cache entries for " + name);
            try {
                cache.rebuild();
            } catch (final RuntimeException e) {
                LOGGER.error(e.getMessage(), e);
            }
        });
    }
Removes all items from all caches and rebuilds it from config
stroom-cache/stroom-cache-service-impl/src/main/java/stroom/cache/service/impl/CacheManagerServiceImpl.java