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 c8bcb42b7c06ff61025c0c1e1e36db9830f0657d..fd1b8f3f4bdc7c673937e49eb060290762c55c2e 100644
--- a/core/src/main/java/com/yahoo/ycsb/generator/AcknowledgedCounterGenerator.java
+++ b/core/src/main/java/com/yahoo/ycsb/generator/AcknowledgedCounterGenerator.java
@@ -21,12 +21,19 @@ public class AcknowledgedCounterGenerator extends CounterGenerator
 		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);