private ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
public LockHolder lockForWriting() {
ReentrantReadWriteLock.WriteLock wLock = lock.writeLock();
private ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
public LockHolder lockForWriting() {
ReentrantReadWriteLock.WriteLock wLock = lock.writeLock();