Reorganize Java SDK readme content (#83)

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

Fix lint.

* Update README.md

* Update README.md

* Update README.md

README.md

@@ -1,54 +1,55 @@
-# milvus-sdk-java
+# Milvus Java SDK
 
 [![Maven Central](https://img.shields.io/maven-central/v/io.milvus/milvus-sdk-java.svg)](https://search.maven.org/artifact/io.milvus/milvus-sdk-java/)
 
-Java SDK for [Milvus](https://github.com/milvus-io/milvus) distributed high-performance vector search engine. 
-If you want to contribute to this repo, please read our [contribution guidelines](https://github.com/milvus-io/milvus/blob/master/CONTRIBUTING.md).
+Java SDK for [Milvus](https://github.com/milvus-io/milvus). To contribute code to this project, please read our [contribution guidelines](https://github.com/milvus-io/milvus/blob/master/CONTRIBUTING.md) first.
 
 ## Getting started
 
-You will need Java 8 or higher.
+### Prerequisites
 
-Milvus version compatibility:
+    - Java 8 or higher
+    - Apache Maven or Gradle/Grails
 
-|Milvus version| SDK version|
-|:-----:|:-----:|
-| 0.5.0 | 0.2.2 | 
-| 0.5.1 | 0.2.2 | 
-| 0.5.2 | 0.2.2 | 
-| 0.5.3 | 0.3.0 | 
-| 0.6.0 | 0.4.1 | 
+The following table shows compatibilities between Milvus and Java SDK.
 
-### Dependency 
+   | Milvus version | SDK version |
+   | :------------: | :---------: |
+   |     0.5.0      |    0.2.2    |
+   |     0.5.1      |    0.2.2    |
+   |     0.5.2      |    0.2.2    |
+   |     0.5.3      |    0.3.0    |
+   |     0.6.0      |    0.4.1    |
+   |     0.7.0      |    0.5.0    |
 
-Apache Maven
-```xml
-<dependency>
-    <groupId>io.milvus</groupId>
-    <artifactId>milvus-sdk-java</artifactId>
-    <version>0.4.1</version>
-</dependency>
-```
+### Install Java SDK
 
-Gradle/Grails 
+You can use **Apache Maven** or **Gradle**/**Grails** to download the SDK.
 
-`compile 'io.milvus:milvus-sdk-java:0.4.1'`
+   - Apache Maven
+
+       ```xml
+        <dependency>
+            <groupId>io.milvus</groupId>
+            <artifactId>milvus-sdk-java</artifactId>
+            <version>0.5.0</version>
+        </dependency>
+       ```
+
+   - Gradle/Grails
+
+        ```gradle
+        compile 'io.milvus:milvus-sdk-java:0.5.0'
+        ```
 
 ### Examples
 
-Please refer to [examples](https://github.com/milvus-io/milvus-sdk-java/tree/master/examples) folder
+Please refer to [examples](https://github.com/milvus-io/milvus-sdk-java/tree/master/examples) folder for Java example programs.
 
 ### Documentation
 
 - [Javadoc](https://milvus-io.github.io/milvus-sdk-java/javadoc/index.html)
-- [Milvus doc](https://milvus.io/docs/en/userguide/install_milvus/)
 
 ### Additional information
 
 - The Java source code is formatted using [google-java-format](https://github.com/google/google-java-format).
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