public Object getLock() {
    return lock;
  }
A copy constructor used for creating a new oplog based on the previous Oplog. This constructor
is invoked only from the function switchOplog

@param oplogId integer identifying the new oplog
@param dirHolder The directory in which to create new Oplog
@param prevOplog The previous oplog
geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java