[GitHub] [flink] zentol commented on a change in pull request #9169: [FLINK-12998][docs] Update documentation for file systems loading as plugins

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zentol commented on a change in pull request #9169: [FLINK-12998][docs] Update documentation for file systems loading as plugins
URL: https://github.com/apache/flink/pull/9169#discussion_r304921646
 
 

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 File path: docs/ops/filesystems/index.md
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 @@ -83,17 +101,21 @@ fs.hdfs.hadoopconf: /path/to/etc/hadoop
 This registers `/path/to/etc/hadoop` as Hadoop's configuration directory and is where Flink will look for the `core-site.xml` and `hdfs-site.xml` files.
 
 
-## Adding new File System Implementations
+## Adding a new pluggable File System implementation
 
-File systems are represented via the `org.apache.flink.core.fs.FileSystem` class, which captures the ways to access and modify files and objects in that file system. 
-Implementations are discovered by Flink through Java's service abstraction, making it easy to add new file system implementations.
+File systems are represented via the `org.apache.flink.core.fs.FileSystem` class, which captures the ways to access and modify files and objects in that file system.
 
 To add a new file system:
 
   - Add the File System implementation, which is a subclass of `org.apache.flink.core.fs.FileSystem`.
   - Add a factory that instantiates that file system and declares the scheme under which the FileSystem is registered. This must be a subclass of `org.apache.flink.core.fs.FileSystemFactory`.
-  - Add a service entry. Create a file `META-INF/services/org.apache.flink.core.fs.FileSystemFactory` which contains the class name of your file system factory class.
+  - Add a service entry. Create a file `META-INF/services/org.apache.flink.core.fs.FileSystemFactory` which contains the class name of your file system factory class
+  (see the [Java Service Loader docs](https://docs.oracle.com/javase/8/docs/api/java/util/ServiceLoader.html) for more details).
+
+During plugins discovery, the file system factory class would be loaded by a dedicated Java class loader to avoid class conflicts with other plugins and Flink components.
+The same class loader should be used during file system instantiation and the file system operation calls.
 
 Review comment:
   ```suggestion
   The same class loader will be used during file system instantiation and the file system operation calls.
   ```

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