diff --git a/core/src/main/java/com/yahoo/ycsb/generator/AcknowledgedCounterGenerator.java b/core/src/main/java/com/yahoo/ycsb/generator/AcknowledgedCounterGenerator.java
index c8bcb42b..fd1b8f3f 100644
--- a/core/src/main/java/com/yahoo/ycsb/generator/AcknowledgedCounterGenerator.java
+++ b/core/src/main/java/com/yahoo/ycsb/generator/AcknowledgedCounterGenerator.java
@@ -1,43 +1,50 @@
 package com.yahoo.ycsb.generator;
 
 import java.util.PriorityQueue;
 
 /**
  * A CounterGenerator that reports generated integers via lastInt()
  * only after they have been acknowledged.
  */
 public class AcknowledgedCounterGenerator extends CounterGenerator
 {
 	private PriorityQueue<Integer> ack;
 	private int limit;
 
 	/**
 	 * Create a counter that starts at countstart.
 	 */
 	public AcknowledgedCounterGenerator(int countstart)
 	{
 		super(countstart);
 		ack = new PriorityQueue<Integer>();
 		limit = countstart - 1;
 	}
 
+	/**
+	 * In this generator, the highest acknowledged counter value
+	 * (as opposed to the highest generated counter value).
+	 */
 	@Override
 	public int lastInt()
 	{
 		return limit;
 	}
 
+	/**
+	 * Make a generated counter value available via lastInt().
+	 */
 	public synchronized void acknowledge(int value)
 	{
 		ack.add(value);
 
 		// move a contiguous sequence from the priority queue
 		// over to the "limit" variable
 
 		Integer min;
 
 		while ((min = ack.peek()) != null && min == limit + 1) {
 			limit = ack.poll();
 		}
 	}
 }