diff --git a/pom.xml b/pom.xml
index 164c0da..f11c446 100755
--- a/pom.xml
+++ b/pom.xml
@@ -81,7 +81,11 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>
-        <version>2.7</version>
+        <version>2.8</version>
+	<configuration>
+	  <charset>UTF-8</charset>
+	  <locale>en_US</locale>
+	</configuration>
         <executions>
           <execution>
             <id>attach-javadocs</id>
diff --git a/src/main/java/org/xerial/snappy/SnappyCodec.java b/src/main/java/org/xerial/snappy/SnappyCodec.java
index 35d5b27..18014bd 100755
--- a/src/main/java/org/xerial/snappy/SnappyCodec.java
+++ b/src/main/java/org/xerial/snappy/SnappyCodec.java
@@ -33,7 +33,16 @@ import java.io.OutputStream;
 import java.util.Arrays;
 
 /**
- * Preamble header for {@link SnappyOutputStream}
+ * Preamble header for {@link SnappyOutputStream}.
+ * 
+ * <p>
+ * The magic header is the following 8 bytes data:
+ * 
+ * <pre>
+ * -126, 'S', 'N', 'A', 'P', 'P', 'Y', 0
+ * </pre>
+ * 
+ * </p>
  * 
  * @author leo
  * 
diff --git a/src/main/java/org/xerial/snappy/SnappyInputStream.java b/src/main/java/org/xerial/snappy/SnappyInputStream.java
index 2668cc5..51c5d4e 100755
--- a/src/main/java/org/xerial/snappy/SnappyInputStream.java
+++ b/src/main/java/org/xerial/snappy/SnappyInputStream.java
@@ -34,10 +34,6 @@ import java.io.InputStream;
  * @author leo
  * 
  */
-/**
- * @author leo
- * 
- */
 public class SnappyInputStream extends InputStream
 {
     private boolean             finishedReading    = false;
@@ -132,7 +128,7 @@ public class SnappyInputStream extends InputStream
      * @param array
      * @param byteOffset
      * @param byteLength
-     * @return
+     * @return written bytes
      * @throws IOException
      */
     public int rawRead(Object array, int byteOffset, int byteLength) throws IOException {
diff --git a/src/main/java/org/xerial/snappy/SnappyLoader.java b/src/main/java/org/xerial/snappy/SnappyLoader.java
index f702fb4..511723c 100755
--- a/src/main/java/org/xerial/snappy/SnappyLoader.java
+++ b/src/main/java/org/xerial/snappy/SnappyLoader.java
@@ -453,7 +453,7 @@ public class SnappyLoader
      * This version data is used as a suffix of a dll file extracted from the
      * jar.
      * 
-     * @return
+     * @return the version string
      */
     public static String getVersion() {
 
diff --git a/src/main/java/org/xerial/snappy/SnappyNative.java b/src/main/java/org/xerial/snappy/SnappyNative.java
index 6dc055f..7070d1d 100755
--- a/src/main/java/org/xerial/snappy/SnappyNative.java
+++ b/src/main/java/org/xerial/snappy/SnappyNative.java
@@ -32,8 +32,10 @@ import java.nio.ByteBuffer;
  * method in this class is defined in SnappyNative.h (genereted by javah) and
  * SnappyNative.cpp
  * 
- * NEVER USE THIS CLASS DIRECTLY since it breaks the native library code
- * loading.
+ * <p>
+ * <b> DO NOT USE THIS CLASS DIRECTLY since the direct use of this class might
+ * break the native library code loading in {@link SnappyLoader}. </b>
+ * </p>
  * 
  * @author leo
  * 
diff --git a/src/main/java/org/xerial/snappy/SnappyNativeAPI.java b/src/main/java/org/xerial/snappy/SnappyNativeAPI.java
index 50881b4..36989d9 100755
--- a/src/main/java/org/xerial/snappy/SnappyNativeAPI.java
+++ b/src/main/java/org/xerial/snappy/SnappyNativeAPI.java
@@ -28,7 +28,8 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 
 /**
- * Interface to access the native code of Snappy.
+ * Interface to access the native code of Snappy. Although this class members
+ * are public, do not use them directly. Use {@link Snappy} API instead.
  * 
  * 
  * @author leo
diff --git a/src/main/java/org/xerial/snappy/SnappyOutputStream.java b/src/main/java/org/xerial/snappy/SnappyOutputStream.java
index ba4d541..786606a 100755
--- a/src/main/java/org/xerial/snappy/SnappyOutputStream.java
+++ b/src/main/java/org/xerial/snappy/SnappyOutputStream.java
@@ -38,7 +38,6 @@ import java.io.OutputStream;
  * <ol>
  * <li>snappy codec header defined in {@link SnappyCodec}
  * <li>a pair of (compressed data size, compressed data...)
- * <li>a pair of (compressed data size, compressed data...)
  * <li>...
  * </ol>
  *