LocalNodeRecordStore possible concurrency issue when updated it on DiscoveryManagerImpl

[meldsun0]

Given this method on LocalNodeRecordStore:

    public void onCustomFieldValueChanged(String fieldName, Bytes value) {
        NodeRecord oldRecord = this.latestRecord;
        NodeRecord newRecord = oldRecord.withUpdatedCustomField(fieldName, value, this.secretKey);
        this.latestRecord = newRecord;
        this.recordListener.recordUpdated(oldRecord, newRecord);
    }

There can be a concurrency issue even though latestRecord is declared volatile:

NodeRecord oldRecord = this.latestRecord;
// ...create newRecord based on oldRecord...
this.latestRecord = newRecord;

If two threads call this method at the same time, they may:

Both read the same oldRecord.

Both compute a different newRecord.

Both assign a latestRecord, but the second thread silently overwrites the first one's update.

Suggestions:

• Use synchronized block
• Use AtomicReference