Documentation

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1298506 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java b/src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java
index 7200356..8164970 100644
--- a/src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java
+++ b/src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java
@@ -135,6 +135,15 @@
      */
     private static final ThreadLocal<WeakHashMap<Object, Object>> REGISTRY =
         new ThreadLocal<WeakHashMap<Object,Object>>();
+    /*
+     * Note that objects of this class are generally shared between threads, so
+     * an instance variable would not be suitable here.
+     * 
+     * In normal use the registry should always be left empty, because the caller
+     * should call toString() which will clean up.
+     * 
+     * See LANG-792
+     */
 
     /**
      * <p>