doc: improve readme for java version and example

README-CN.md

@@ -18,7 +18,7 @@
 
 1. 要使用 Alibaba Cloud SDK for Java ，您需要一个云账号以及一对`Access Key ID`和`Access Key Secret`。 请在阿里云控制台中的[RAM管理页面](https://ram.console.aliyun.com)上创建和查看您的Access Key，或者联系您的系统管理员。
 2. 要使用 Alibaba Cloud SDK for Java 访问某个产品的API，您需要事先在[阿里云控制台](https://home.console.aliyun.com)中开通这个产品。
-3. Alibaba Cloud SDK for Java 需要1.6以上的JDK。
+3. Alibaba Cloud SDK for Java 需要 1.8 以上的 JDK。
 
 ## 安装依赖
 
@@ -68,32 +68,32 @@
 
 ## 快速使用
 
-以下这个代码示例向您展示了调用 Alibaba Cloud SDK for Java 的3个主要步骤：
-
-1. 创建DefaultAcsClient实例并初始化。
-2. 创建API请求并设置参数。
-3. 发起请求并处理应答或异常。
+以下这个代码示例向您展示了如何调用 Alibaba Cloud SDK for Java：
 
 ```java
 package com.testprogram;
+
 import com.aliyuncs.profile.DefaultProfile;
 import com.aliyuncs.DefaultAcsClient;
 import com.aliyuncs.IAcsClient;
 import com.aliyuncs.exceptions.ClientException;
 import com.aliyuncs.exceptions.ServerException;
 import com.aliyuncs.ecs.model.v20140526.*;
+
 public class Main {
     public static void main(String[] args) {
-         // 创建DefaultAcsClient实例并初始化
+        // 1. 创建DefaultAcsClient实例并初始化。
         DefaultProfile profile = DefaultProfile.getProfile(
             "<your-region-id>",          // 地域ID
             "<your-access-key-id>",      // RAM账号的AccessKey ID
             "<your-access-key-secret>"); // RAM账号Access Key Secret
         IAcsClient client = new DefaultAcsClient(profile);
-         // 创建API请求并设置参数
+
+        // 2. 创建API请求并设置参数
         DescribeInstancesRequest request = new DescribeInstancesRequest();
         request.setPageSize(10);
-        // 发起请求并处理应答或异常
+
+        // 3. 发起请求并处理应答或异常
         DescribeInstancesResponse response;
         try {
             response = client.getAcsResponse(request);
@@ -109,6 +109,8 @@ public class Main {
 }
 ```
 
+> 因为安全的原因，我们不推荐在源代码中硬编码凭证信息。你应该通过外部配置或者环境变量的方式来访问凭证信息。
+
 ## 文档
 
 * [环境要求](./docs/0-Requirements-CN.md)

README.md

@@ -19,10 +19,8 @@ If you have any problem while using Alibaba Cloud SDK for Java, please [submit a
 ## Requirements
 
 - To use Alibaba Cloud SDK for Java, you must have an Alibaba Cloud account as well as an `AccessKey ID` and an `AccessKey Secret`. Create and view your AccessKey on the [RAM console](https://ram.console.aliyun.com "RAM console") or contact your system administrator.
-
 - To use the Alibaba Cloud SDK for Java to access the APIs of a product, you must first activate the product on the [Alibaba Cloud console](https://home.console.aliyun.com) if required.
-
-- The Alibaba Cloud Java SDK requires JDK 1.6 or later.
+- The Alibaba Cloud Java SDK requires JDK 1.8 or later.
 
 ## Installation
 
@@ -71,34 +69,32 @@ If maven is not downloading jar packages from a central repository, you need to
 
 ## Quick Examples
 
-The following code example shows the three main steps to use Alibaba Cloud SDK for Java :
-
-1. Create and initialize a `DefaultAcsClient` instance.
-
-2. Create an API request and set parameters.
-
-3. Initiate the request and handle the response or exceptions.
+The following code example shows how to use Alibaba Cloud SDK for Java :
 
 ```java
 package com.testprogram;
+
 import com.aliyuncs.profile.DefaultProfile;
 import com.aliyuncs.DefaultAcsClient;
 import com.aliyuncs.IAcsClient;
 import com.aliyuncs.exceptions.ClientException;
 import com.aliyuncs.exceptions.ServerException;
 import com.aliyuncs.ecs.model.v20140526.*;
+
 public class Main {
     public static void main(String[] args) {
-        // Create and initialize a DefaultAcsClient instance
+        // 1. Create and initialize a DefaultAcsClient instance
         DefaultProfile profile = DefaultProfile.getProfile(
             "<your-region-id>",          // The region ID
             "<your-access-key-id>",      // The AccessKey ID of the RAM account
             "<your-access-key-secret>"); // The AccessKey Secret of the RAM account
         IAcsClient client = new DefaultAcsClient(profile);
-        // Create an API request and set parameters
+
+        // 2. Create an API request and set parameters
         DescribeInstancesRequest request = new DescribeInstancesRequest();
         request.setPageSize(10);
-        // Initiate the request and handle the response or exceptions
+
+        // 3. Initiate the request and handle the response or exceptions
         DescribeInstancesResponse response;
         try {
             response = client.getAcsResponse(request);
@@ -114,6 +110,9 @@ public class Main {
 }
 ```
 
+> For security reason, we don't recommend to hard code credentials information in source code. You should access
+> credentials from external configurations or environment variables.
+
 ## Documentation
 
 - [Requirements](./docs/0-Requirements-EN.md)