Keep in mind that AtomicLong has extra functionality to deal with
thread-safety.  If you know you don't need thread safety, I would
suggest writing your own wrapper.

More specically, I'm assuming your "long" value actually has a
semantic meaning.  For instance, numberOfSheep.

public class SheepCounter {
  private long numberOfSheep;
  public Long getNumberOfSheep() {
     return numberOfSheep;
  }
  public void count() {
      numberOfSheep++;
  }
  public void setNumberOfSheep(long numberOfSheep) {
    this.numberOfSheep = numberOfSheep;
  }
}

Avoid primative obsession where it makes sense.  You might find that
the class can start taking on more behavior, and you'll end up with
better design.