From 77dbfbed73a5a5fdd69b53bc5b70c8d23bf6750d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=A9=AC=E9=87=91=E5=87=AF?= <majk@vip.qq.com>
Date: Tue, 8 Jan 2019 10:54:51 +0800
Subject: [PATCH] Add javadoc for dubbo-serialization module(#3002). (#3004)

Add javadoc for dubbo-serialization module(#3002).
---
 .../dubbo/common/serialize/Cleanable.java     |  6 +++++
 .../dubbo/common/serialize/DataInput.java     |  2 +-
 .../dubbo/common/serialize/DataOutput.java    |  8 +++---
 .../dubbo/common/serialize/ObjectInput.java   | 25 ++++++++++++-------
 .../dubbo/common/serialize/ObjectOutput.java  |  2 +-
 .../dubbo/common/serialize/Serialization.java | 23 ++++++++++-------
 .../support/SerializableClassRegistry.java    | 14 +++++++++++
 .../support/SerializationOptimizer.java       |  8 ++++--
 .../fastjson/FastJsonObjectInput.java         |  3 +++
 .../fastjson/FastJsonObjectOutput.java        |  3 +++
 .../fastjson/FastJsonSerialization.java       |  7 ++++++
 .../common/serialize/fst/FstFactory.java      |  3 +++
 .../common/serialize/fst/FstObjectInput.java  |  4 ++-
 .../common/serialize/fst/FstObjectOutput.java |  4 ++-
 .../serialize/fst/FstSerialization.java       |  7 ++++++
 .../hessian2/Hessian2ObjectInput.java         |  2 +-
 .../hessian2/Hessian2ObjectOutput.java        |  2 +-
 .../hessian2/Hessian2Serialization.java       |  7 ++++++
 .../java/CompactedJavaSerialization.java      |  7 ++++++
 .../java/CompactedObjectInputStream.java      |  2 +-
 .../java/CompactedObjectOutputStream.java     |  2 +-
 .../serialize/java/JavaObjectInput.java       |  2 +-
 .../serialize/java/JavaObjectOutput.java      |  2 +-
 .../serialize/java/JavaSerialization.java     |  7 ++++++
 .../nativejava/NativeJavaObjectInput.java     |  3 +++
 .../nativejava/NativeJavaObjectOutput.java    |  3 +++
 .../nativejava/NativeJavaSerialization.java   |  7 ++++++
 .../serialize/kryo/KryoObjectInput.java       |  3 +++
 .../serialize/kryo/KryoObjectOutput.java      |  3 +++
 .../serialize/kryo/KryoSerialization.java     |  3 +++
 .../protostuff/ProtostuffObjectInput.java     |  3 +++
 .../protostuff/ProtostuffObjectOutput.java    |  3 +++
 .../protostuff/ProtostuffSerialization.java   |  7 ++++++
 .../protostuff/delegate/TimeDelegate.java     |  3 +++
 .../protostuff/utils/WrapperUtils.java        | 15 +++++++++++
 35 files changed, 171 insertions(+), 34 deletions(-)

diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Cleanable.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Cleanable.java
index a8f96d3b0e9..425bb0a4ede 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Cleanable.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Cleanable.java
@@ -16,7 +16,13 @@
  */
 package org.apache.dubbo.common.serialize;
 
+/**
+ * Interface defines that the object is cleanable.
+ */
 public interface Cleanable {
 
+    /**
+     * Implementations must implement this cleanup method
+     */
     void cleanup();
 }
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataInput.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataInput.java
index d122e5cfa13..7930d04d101 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataInput.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataInput.java
@@ -19,7 +19,7 @@
 import java.io.IOException;
 
 /**
- * Data input.
+ * Basic data type input interface.
  */
 public interface DataInput {
 
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataOutput.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataOutput.java
index 36577240427..58973271542 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataOutput.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/DataOutput.java
@@ -19,7 +19,7 @@
 import java.io.IOException;
 
 /**
- * Data output.
+ * Basic data type output interface.
  */
 public interface DataOutput {
 
@@ -98,9 +98,9 @@ public interface DataOutput {
     /**
      * Write byte array.
      *
-     * @param v   value.
-     * @param off offset.
-     * @param len length.
+     * @param v value.
+     * @param off the start offset in the data.
+     * @param len the number of bytes that are written.
      * @throws IOException
      */
     void writeBytes(byte[] v, int off, int len) throws IOException;
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectInput.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectInput.java
index 81207cb720a..1d8646e880e 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectInput.java
@@ -20,30 +20,37 @@
 import java.lang.reflect.Type;
 
 /**
- * Object input.
+ * Object input interface.
  */
 public interface ObjectInput extends DataInput {
 
     /**
-     * read object.
+     * read object
      *
-     * @return object.
+     * @return object
+     * @throws IOException if an I/O error occurs
+     * @throws ClassNotFoundException if an ClassNotFoundException occurs
      */
     Object readObject() throws IOException, ClassNotFoundException;
 
     /**
-     * read object.
+     * read object
      *
-     * @param cls object type.
-     * @return object.
+     * @param cls object class
+     * @return object
+     * @throws IOException if an I/O error occurs
+     * @throws ClassNotFoundException if an ClassNotFoundException occurs
      */
     <T> T readObject(Class<T> cls) throws IOException, ClassNotFoundException;
 
     /**
-     * read object.
+     * read object
      *
-     * @param cls object type.
-     * @return object.
+     * @param cls object class
+     * @param type object type
+     * @return object
+     * @throws IOException if an I/O error occurs
+     * @throws ClassNotFoundException if an ClassNotFoundException occurs
      */
     <T> T readObject(Class<T> cls, Type type) throws IOException, ClassNotFoundException;
 
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectOutput.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectOutput.java
index bf50167d810..73fa3b61fd5 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/ObjectOutput.java
@@ -19,7 +19,7 @@
 import java.io.IOException;
 
 /**
- * Object output.
+ * Object output interface.
  */
 public interface ObjectOutput extends DataOutput {
 
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Serialization.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Serialization.java
index eb9a72e98fd..0c09df99a3d 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Serialization.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/Serialization.java
@@ -25,30 +25,35 @@
 import java.io.OutputStream;
 
 /**
- * Serialization. (SPI, Singleton, ThreadSafe)
+ * Serialization strategy interface that specifies a serializer. (SPI, Singleton, ThreadSafe)
+ *
+ * The default extension is hessian2 and the default serialization implementation of the dubbo protocol.
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="xxx" /&gt;
+ * </pre>
  */
 @SPI("hessian2")
 public interface Serialization {
 
     /**
-     * get content type id
+     * Get content type unique id, recommended that custom implementations use values greater than 20.
      *
      * @return content type id
      */
     byte getContentTypeId();
 
     /**
-     * get content type
+     * Get content type
      *
      * @return content type
      */
     String getContentType();
 
     /**
-     * create serializer
+     * Get a serialization implementation instance
      *
-     * @param url
-     * @param output
+     * @param url URL address for the remote service
+     * @param output the underlying output stream
      * @return serializer
      * @throws IOException
      */
@@ -56,10 +61,10 @@ public interface Serialization {
     ObjectOutput serialize(URL url, OutputStream output) throws IOException;
 
     /**
-     * create deserializer
+     * Get a deserialization implementation instance
      *
-     * @param url
-     * @param input
+     * @param url URL address for the remote service
+     * @param input the underlying input stream
      * @return deserializer
      * @throws IOException
      */
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializableClassRegistry.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializableClassRegistry.java
index 2ebb3a3c7fd..22de45d5c74 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializableClassRegistry.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializableClassRegistry.java
@@ -21,6 +21,10 @@
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+/**
+ * Provide a unified serialization registry, this class used for {@code dubbo-serialization-fst}
+ * and {@code dubbo-serialization-kryo}, it will register some classes at startup time (for example {@link AbstractKryoFactory#create})
+ */
 public abstract class SerializableClassRegistry {
 
 
@@ -28,6 +32,8 @@ public abstract class SerializableClassRegistry {
 
     /**
      * only supposed to be called at startup time
+     *
+     * @param clazz object type
      */
     public static void registerClass(Class clazz) {
         registerClass(clazz, null);
@@ -35,6 +41,9 @@ public static void registerClass(Class clazz) {
 
     /**
      * only supposed to be called at startup time
+     *
+     * @param clazz object type
+     * @param serializer object serializer
      */
     public static void registerClass(Class clazz, Serializer serializer) {
         if (clazz == null) {
@@ -43,6 +52,11 @@ public static void registerClass(Class clazz, Serializer serializer) {
         registrations.put(clazz, serializer);
     }
 
+    /**
+     * get registered classes
+     *
+     * @return class serializer
+     * */
     public static Map<Class, Object> getRegisteredClasses() {
         return registrations;
     }
diff --git a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializationOptimizer.java b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializationOptimizer.java
index 7085f2de89a..b043f3448f8 100644
--- a/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializationOptimizer.java
+++ b/dubbo-serialization/dubbo-serialization-api/src/main/java/org/apache/dubbo/common/serialize/support/SerializationOptimizer.java
@@ -19,10 +19,14 @@
 import java.util.Collection;
 
 /**
- * This class can be replaced with the contents in config file, but for now I think the class is easier to write
- *
+ * Interface defining serialization optimizer, there are nothing implementations for now.
  */
 public interface SerializationOptimizer {
 
+    /**
+     * Get serializable classes
+     *
+     * @return serializable classes
+     * */
     Collection<Class> getSerializableClasses();
 }
diff --git a/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectInput.java b/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectInput.java
index 96824fd58cf..1a38f277dc7 100644
--- a/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectInput.java
@@ -29,6 +29,9 @@
 import java.io.Reader;
 import java.lang.reflect.Type;
 
+/**
+ * FastJson object input implementation
+ */
 public class FastJsonObjectInput implements ObjectInput {
 
     private final BufferedReader reader;
diff --git a/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectOutput.java b/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectOutput.java
index d0e4ed546e9..3f9ec2083da 100644
--- a/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonObjectOutput.java
@@ -28,6 +28,9 @@
 import java.io.PrintWriter;
 import java.io.Writer;
 
+/**
+ * FastJson object output implementation
+ */
 public class FastJsonObjectOutput implements ObjectOutput {
 
     private final PrintWriter writer;
diff --git a/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonSerialization.java b/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonSerialization.java
index 189ef0b0b86..097587132c7 100644
--- a/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-fastjson/src/main/java/org/apache/dubbo/common/serialize/fastjson/FastJsonSerialization.java
@@ -25,6 +25,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * FastJson serialization implementation
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="fastjson" /&gt;
+ * </pre>
+ */
 public class FastJsonSerialization implements Serialization {
 
     @Override
diff --git a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstFactory.java b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstFactory.java
index b0830332b52..e41c358b43e 100644
--- a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstFactory.java
+++ b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstFactory.java
@@ -25,6 +25,9 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Fst object input/output factory
+ */
 public class FstFactory {
 
     private static final FstFactory factory = new FstFactory();
diff --git a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectInput.java b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectInput.java
index b94a85f2fd8..51e8340a988 100644
--- a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectInput.java
@@ -24,7 +24,9 @@
 import java.io.InputStream;
 import java.lang.reflect.Type;
 
-
+/**
+ * Fst object input implementation
+ */
 public class FstObjectInput implements ObjectInput {
 
     private FSTObjectInput input;
diff --git a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectOutput.java b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectOutput.java
index 46fee0b3aa0..a2c40e5d0da 100644
--- a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstObjectOutput.java
@@ -23,7 +23,9 @@
 import java.io.IOException;
 import java.io.OutputStream;
 
-
+/**
+ * Fst object output implementation
+ */
 public class FstObjectOutput implements ObjectOutput {
 
     private FSTObjectOutput output;
diff --git a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstSerialization.java b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstSerialization.java
index 89881df3969..e8b984c8bba 100644
--- a/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-fst/src/main/java/org/apache/dubbo/common/serialize/fst/FstSerialization.java
@@ -25,6 +25,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Fst serialization implementation
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="fst" /&gt;
+ * </pre>
+ */
 public class FstSerialization implements Serialization {
 
     @Override
diff --git a/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectInput.java b/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectInput.java
index 348d04d9913..d1ef21402c7 100644
--- a/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectInput.java
@@ -25,7 +25,7 @@
 import java.lang.reflect.Type;
 
 /**
- * Hessian2 Object input.
+ * Hessian2 object input implementation
  */
 public class Hessian2ObjectInput implements ObjectInput {
     private final Hessian2Input mH2i;
diff --git a/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectOutput.java b/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectOutput.java
index fec356a668a..38fd3db0b27 100644
--- a/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2ObjectOutput.java
@@ -24,7 +24,7 @@
 import java.io.OutputStream;
 
 /**
- * Hessian2 Object output.
+ * Hessian2 object output implementation
  */
 public class Hessian2ObjectOutput implements ObjectOutput {
     private final Hessian2Output mH2o;
diff --git a/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2Serialization.java b/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2Serialization.java
index 71c6233659c..225df10908a 100644
--- a/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2Serialization.java
+++ b/dubbo-serialization/dubbo-serialization-hessian2/src/main/java/org/apache/dubbo/common/serialize/hessian2/Hessian2Serialization.java
@@ -25,6 +25,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Hessian2 serialization implementation, hessian2 is the default serialization protocol for dubbo
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="hessian2" /&gt;
+ * </pre>
+ */
 public class Hessian2Serialization implements Serialization {
 
     public static final byte ID = 2;
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedJavaSerialization.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedJavaSerialization.java
index 9573ed77891..8222ac45091 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedJavaSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedJavaSerialization.java
@@ -25,6 +25,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Compacted java serialization implementation
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="compactedjava" /&gt;
+ * </pre>
+ */
 public class CompactedJavaSerialization implements Serialization {
 
     @Override
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectInputStream.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectInputStream.java
index a6bda0aca99..2ed71f814ec 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectInputStream.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectInputStream.java
@@ -26,7 +26,7 @@
 import java.io.StreamCorruptedException;
 
 /**
- * Compacted java object input stream.
+ * Compacted java object input implementation
  */
 public class CompactedObjectInputStream extends ObjectInputStream {
     private ClassLoader mClassLoader;
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectOutputStream.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectOutputStream.java
index 2bbf42e97eb..56847e5e254 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectOutputStream.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/CompactedObjectOutputStream.java
@@ -22,7 +22,7 @@
 import java.io.OutputStream;
 
 /**
- * Compacted java object output stream.
+ * Compacted java object output implementation
  */
 public class CompactedObjectOutputStream extends ObjectOutputStream {
     public CompactedObjectOutputStream(OutputStream out) throws IOException {
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectInput.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectInput.java
index 00e712e6e97..936ab265063 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectInput.java
@@ -24,7 +24,7 @@
 import java.lang.reflect.Type;
 
 /**
- * Java Object input.
+ * Java object input implementation
  */
 public class JavaObjectInput extends NativeJavaObjectInput {
     public final static int MAX_BYTE_ARRAY_LENGTH = 8 * 1024 * 1024;
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectOutput.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectOutput.java
index 49a4b45123f..0e78747c919 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaObjectOutput.java
@@ -23,7 +23,7 @@
 import java.io.OutputStream;
 
 /**
- * Java Object output.
+ * Java object output implementation
  */
 public class JavaObjectOutput extends NativeJavaObjectOutput {
     public JavaObjectOutput(OutputStream os) throws IOException {
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaSerialization.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaSerialization.java
index 72d9ef3a94d..bf98818fd43 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/java/JavaSerialization.java
@@ -25,6 +25,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Java serialization implementation
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="java" /&gt;
+ * </pre>
+ */
 public class JavaSerialization implements Serialization {
 
     @Override
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectInput.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectInput.java
index a01f1ebaa73..c791250f7af 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectInput.java
@@ -25,6 +25,9 @@
 import java.io.ObjectInputStream;
 import java.lang.reflect.Type;
 
+/**
+ * Native java object input implementation
+ */
 public class NativeJavaObjectInput implements ObjectInput {
 
     private final ObjectInputStream inputStream;
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectOutput.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectOutput.java
index 89f8145a68f..2ff82f76c36 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaObjectOutput.java
@@ -24,6 +24,9 @@
 import java.io.ObjectOutputStream;
 import java.io.OutputStream;
 
+/**
+ * Native java object output implementation
+ */
 public class NativeJavaObjectOutput implements ObjectOutput {
 
     private final ObjectOutputStream outputStream;
diff --git a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaSerialization.java b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaSerialization.java
index 3b692487445..55198690607 100644
--- a/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-jdk/src/main/java/org/apache/dubbo/common/serialize/nativejava/NativeJavaSerialization.java
@@ -26,6 +26,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Native java serialization implementation
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="nativejava" /&gt;
+ * </pre>
+ */
 public class NativeJavaSerialization implements Serialization {
 
     public static final String NAME = "nativejava";
diff --git a/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectInput.java b/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectInput.java
index fcfc91a4fe5..91648e5c628 100644
--- a/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectInput.java
@@ -28,6 +28,9 @@
 import java.io.InputStream;
 import java.lang.reflect.Type;
 
+/**
+ * Kryo object input implementation, kryo object can be clean
+ */
 public class KryoObjectInput implements ObjectInput, Cleanable {
 
     private Kryo kryo;
diff --git a/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectOutput.java b/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectOutput.java
index ef2f219acd7..dd127005fe8 100644
--- a/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoObjectOutput.java
@@ -26,6 +26,9 @@
 import java.io.IOException;
 import java.io.OutputStream;
 
+/**
+ * Kryo object output implementation, kryo object can be clean
+ */
 public class KryoObjectOutput implements ObjectOutput, Cleanable {
 
     private Output output;
diff --git a/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoSerialization.java b/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoSerialization.java
index 7ff6617a704..aa10df4af90 100644
--- a/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-kryo/src/main/java/org/apache/dubbo/common/serialize/kryo/KryoSerialization.java
@@ -28,6 +28,9 @@
 /**
  * TODO for now kryo serialization doesn't deny classes that don't implement the serializable interface
  *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="kryo" /&gt;
+ * </pre>
  */
 public class KryoSerialization implements Serialization {
 
diff --git a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectInput.java b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectInput.java
index 0202762cfa2..6284d6a6777 100644
--- a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectInput.java
+++ b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectInput.java
@@ -29,6 +29,9 @@
 import java.io.InputStream;
 import java.lang.reflect.Type;
 
+/**
+ * Protostuff object input implementation
+ */
 public class ProtostuffObjectInput implements ObjectInput {
 
     private DataInputStream dis;
diff --git a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectOutput.java b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectOutput.java
index 2e91d17ef6f..3e54282a6b4 100644
--- a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectOutput.java
+++ b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffObjectOutput.java
@@ -29,6 +29,9 @@
 import java.io.IOException;
 import java.io.OutputStream;
 
+/**
+ * Protostuff object output implementation
+ */
 public class ProtostuffObjectOutput implements ObjectOutput {
 
     private LinkedBuffer buffer = LinkedBuffer.allocate();
diff --git a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffSerialization.java b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffSerialization.java
index aaf5bddc36d..acdeaeaff4c 100644
--- a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffSerialization.java
+++ b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/ProtostuffSerialization.java
@@ -26,6 +26,13 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Protostuff serialization implementation
+ *
+ * <pre>
+ *     e.g. &lt;dubbo:protocol serialization="protostuff" /&gt;
+ * </pre>
+ */
 public class ProtostuffSerialization implements Serialization {
     @Override
     public byte getContentTypeId() {
diff --git a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/delegate/TimeDelegate.java b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/delegate/TimeDelegate.java
index 8cc33c7d0be..6ead01827e2 100644
--- a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/delegate/TimeDelegate.java
+++ b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/delegate/TimeDelegate.java
@@ -26,6 +26,9 @@
 import java.io.IOException;
 import java.sql.Time;
 
+/**
+ * Custom {@link Time} delegate
+ */
 public class TimeDelegate implements Delegate<Time> {
     @Override
     public WireFormat.FieldType getFieldType() {
diff --git a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/utils/WrapperUtils.java b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/utils/WrapperUtils.java
index 9d8be8b4db8..02ea4f0123d 100644
--- a/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/utils/WrapperUtils.java
+++ b/dubbo-serialization/dubbo-serialization-protostuff/src/main/java/org/apache/dubbo/common/serialize/protostuff/utils/WrapperUtils.java
@@ -43,6 +43,9 @@
 import java.util.Vector;
 import java.util.concurrent.ConcurrentHashMap;
 
+/**
+ * Use WrapperUtils to wrap object to {@link Wrapper}
+ */
 public class WrapperUtils {
     private static final Set<Class<?>> WRAPPER_SET = new HashSet<>();
 
@@ -82,10 +85,22 @@ public class WrapperUtils {
 
     }
 
+    /**
+     * Determine if the object needs wrap
+     *
+     * @param clazz object type
+     * @return need wrap
+     */
     public static boolean needWrapper(Class<?> clazz) {
         return WrapperUtils.WRAPPER_SET.contains(clazz) || clazz.isArray() || clazz.isEnum();
     }
 
+    /**
+     * Determine if the object needs wrap
+     *
+     * @param obj object
+     * @return need wrap
+     */
     public static boolean needWrapper(Object obj) {
         return needWrapper(obj.getClass());
     }