Examples of errors detected by the V6102 diagnostic

V6102. Inconsistent synchronization of a field. Consider synchronizing the field on all usages.

Apache Solr

V6102 Inconsistent synchronization of the 'byDirectoryCache' field. Consider synchronizing the field on all usages. CachingDirectoryFactory.java 92, CachingDirectoryFactory.java 228

public abstract class CachingDirectoryFactory extends DirectoryFactory {
  ....
  private static final Logger log = LoggerFactory.getLogger(....);
  protected Map<String, CacheValue> byPathCache = new HashMap<>();
  protected IdentityHashMap<Directory, CacheValue> byDirectoryCache =
                                                  new IdentityHashMap<>();
  ....

  private void removeFromCache(CacheValue v) {
    log.debug("Removing from cache: {}", v);
    byDirectoryCache.remove(v.directory);
    byPathCache.remove(v.path);
  }
}

Apache Kafka

V6102 Inconsistent synchronization of the 'metrics' field. Consider synchronizing the field on all usages. Sensor.java 49, Sensor.java 254

private final Map<MetricName, KafkaMetric> metrics;

public void checkQuotas(long timeMs) {                  // <=
  for (KafkaMetric metric : this.metrics.values()) {
    MetricConfig config = metric.config();
    if (config != null) {
      ....
    }
  }
  ....
}

public synchronized boolean add(CompoundStat stat,      // <=
                                MetricConfig config) {
  ....
  if (!metrics.containsKey(metric.metricName())) {
    metrics.put(metric.metricName(), metric);
  }
  ....
}

public synchronized boolean add(MetricName metricName,  // <=
                                MeasurableStat stat,
                                MetricConfig config) {
  if (hasExpired()) {
    return false;
  } else if (metrics.containsKey(metricName)) {
    return true;
  } else {
    ....
    metrics.put(metric.metricName(), metric);
    return true;
  }
}

Apache Kafka

V6102 Inconsistent synchronization of the 'prefixKeyFormatter' field. Consider synchronizing the field on all usages. LogicalKeyValueSegment.java 60, LogicalKeyValueSegment.java 247

private final PrefixKeyFormatter prefixKeyFormatter;

@Override
public synchronized void destroy() {                // <=
  ....
  Bytes keyPrefix = prefixKeyFormatter.getPrefix();
  ....
}

@Override
public void addToBatch(....) {                      // <=
  physicalStore.addToBatch(
    new KeyValue<>(
    prefixKeyFormatter.addPrefix(record.key),
    record.value
    ), batch
  );
}

@Override
public synchronized void deleteRange(....) {        // <=
  physicalStore.deleteRange(
    prefixKeyFormatter.addPrefix(keyFrom),
    prefixKeyFormatter.addPrefix(keyTo)
  );
}

@Override
public synchronized void put(....) {                // <=
  physicalStore.put(
    prefixKeyFormatter.addPrefix(key),
    value
  );
}