From ecd8aaa3e9112e14516ce56e42330a485de2131a Mon Sep 17 00:00:00 2001
From: "Taro L. Saito" <leo@xerial.org>
Date: Mon, 1 Aug 2011 15:47:02 +0900
Subject: [PATCH] Add comments

---
 .../java/org/xerial/snappy/SnappyLoader.java  | 20 +++++++++++++++----
 .../java/org/xerial/snappy/SnappyNative.java  |  2 +-
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/main/java/org/xerial/snappy/SnappyLoader.java b/src/main/java/org/xerial/snappy/SnappyLoader.java
index 67ccfe8..cc90aa8 100755
--- a/src/main/java/org/xerial/snappy/SnappyLoader.java
+++ b/src/main/java/org/xerial/snappy/SnappyLoader.java
@@ -114,8 +114,8 @@ public class SnappyLoader
 
     /**
      * Load SnappyNative and its JNI native implementation in the root class
-     * loader. This is necessary to avoid JNI multi-loading issues when the same
-     * JNI library is loaded by different class loaders in the same JVM.
+     * loader. This is necessary to avoid the JNI multi-loading issue when the
+     * same JNI library is loaded by different class loaders in the same JVM.
      * 
      * In order to load native code in the root class loader, this method first
      * inject SnappyNativeLoader class into the root class loader, because
@@ -123,14 +123,26 @@ public class SnappyLoader
      * class when loading native libraries.
      * 
      * <pre>
-     * (root class loader) -> [SnappyNativeLoader, SnappyNative, SnappyNativeAPI, SnappyErrorCode]  (injected by this method)
+     * (root class loader) -> [SnappyNativeLoader (load JNI code), SnappyNative (has native methods), SnappyNativeAPI, SnappyErrorCode]  (injected by this method)
      *    |
      *    |
-     * (child class loader) -> See the above classes loaded by the root class loader.
+     * (child class loader) -> Sees the above classes loaded by the root class loader.
      *   Then creates SnappyNativeAPI implementation by instantiating SnappyNaitive class.
      * </pre>
      * 
      * 
+     * <pre>
+     * (root class loader) -> [SnappyNativeLoader, SnappyNative ...]  -> native code is loaded by once in this class loader 
+     *   |   \
+     *   |    (child2 class loader)      
+     * (child1 class loader)
+     * 
+     * child1 and child2 share the same SnappyNative code loaded by the root class loader.
+     * </pre>
+     * 
+     * Note that Java's class loader first delegates the class lookup to its
+     * parent class loader. So once SnappyNativeLoader is loaded by the root
+     * class loader, no child class loader initialize SnappyNativeLoader again.
      * 
      * @return
      */
diff --git a/src/main/java/org/xerial/snappy/SnappyNative.java b/src/main/java/org/xerial/snappy/SnappyNative.java
index 978e5e5..6dc055f 100755
--- a/src/main/java/org/xerial/snappy/SnappyNative.java
+++ b/src/main/java/org/xerial/snappy/SnappyNative.java
@@ -32,7 +32,7 @@ import java.nio.ByteBuffer;
  * method in this class is defined in SnappyNative.h (genereted by javah) and
  * SnappyNative.cpp
  * 
- * NEVER USE THIS CLASS DIRECTROY since it breaks the native library code
+ * NEVER USE THIS CLASS DIRECTLY since it breaks the native library code
  * loading.
  * 
  * @author leo