Added section about Java plugin technique (#625)

* added section about Java plugin technique

* Update plugins/index.md

---------

Co-authored-by: René Jeglinsky <[email protected]>

Author: BraunMatthias

plugins/index.md

@@ -60,8 +60,31 @@ For Node.js all these plugins are implemented using the [`cds-plugin`](../node.j
 
    > → audit logs are written to Audit Log service in production.
 
+## As Plugin for CAP Java
+
+The [CAP Java plugin technique](../java/plugins) makes use of _jar_-files which are distributed as Maven packages.
+By adding an additional Maven dependency to the project, the plugin automatically adds functionality or extensions to the CDS model. 
+For [Audit Logging V2](../java/auditlog#handler-v2) it looks like this:
+
+1. Add the Maven dependency (in _srv/pom.xml_):
+   ```xml
+	<dependency>
+	  <groupId>com.sap.cds</groupId>
+	  <artifactId>cds-feature-auditlog-v2</artifactId>
+	  <scope>runtime</scope>
+	</dependency>
+   ```
+2. Add annotations to your model:
 
+   ```cds
+   annotate Customer with @PersonalData ...;
+   ```
+   > → audit logs are written to console in dev mode.
+   
+3. Bind the platform service.
 
+   > → audit logs are written to SAP Audit Log service.
+   
 
 
 ## GraphQL Adapter