diff --git a/src/java/com/facebook/LinkBench/Link.java b/src/java/com/facebook/LinkBench/Link.java
index 91e3a9c8..bdfa57b6 100644
--- a/src/java/com/facebook/LinkBench/Link.java
+++ b/src/java/com/facebook/LinkBench/Link.java
@@ -72,12 +72,26 @@ public Link clone() {
     return l;
   }
 
+  /** The node id of the source of directed edge */
   public long id1;
-  public long link_type;
+
+  /** The node id of the target of directed edge */
   public long id2;
+
+  /** Type of link */
+  public long link_type;
+
+  /** Visibility mode */
   public byte visibility;
-  public byte[] data;
+
+  /** Version of link */
   public int version;
+
+  /** time is the sort key for links.  Often it contains a timestamp,
+      but it can be used as a arbitrary user-defined sort key. */
   public long time;
 
+  /** Arbitrary payload data */
+  public byte[] data;
+
 }
diff --git a/src/java/com/facebook/LinkBench/Node.java b/src/java/com/facebook/LinkBench/Node.java
index 2b260be1..6e9ed124 100644
--- a/src/java/com/facebook/LinkBench/Node.java
+++ b/src/java/com/facebook/LinkBench/Node.java
@@ -22,10 +22,19 @@
  * @author tarmstrong
  */
 public class Node {
+  /** Unique identifier for node */
   public long id;
+
+  /** Type of node */
   public int type;
+
+  /** Version of node: typically updated on every change */
   public long version;
+
+  /** Last update time of node as UNIX timestamp */
   public int time;
+
+  /** Arbitrary payload data */
   public byte data[];
 
   public Node(long id, int type, long version, int time,