Take CR suggestions

Author: arunkumarchacko

hadoop-tools/hadoop-gcp/src/main/java/org/apache/hadoop/fs/gs/GcsStatistics.java

@@ -53,8 +53,8 @@ enum GcsStatistics {
       TYPE_DURATION);
 
   private final String description;
-  private StatisticTypeEnum type;
-  private String symbol;
+  private final StatisticTypeEnum type;
+  private final String symbol;
 
   StatisticTypeEnum getType() {
     return this.type;

hadoop-tools/hadoop-gcp/src/main/java/org/apache/hadoop/fs/gs/GoogleHadoopFileSystem.java

@@ -110,6 +110,16 @@ public class GoogleHadoopFileSystem extends FileSystem implements IOStatisticsSo
   private GoogleCloudStorageFileSystem gcsFs;
   private boolean isClosed;
   private FsPermission reportedPermissions;
+
+  /**
+   * Setting this to static inorder to have a singleton instance. This will help us get the JVM
+   * level metrics. Note that we use this to generate Global Storage Statistics. If we make this
+   * an instance field, only the first filesystem instance metrics will be updated since while initializing
+   * GlobalStorageStatistics (refer initialize()) only the first instance will be registered.
+   *
+   * For filesystem instance level instrumentation, one more per instance object can be created and both
+   * be updated.
+   */
   private static GcsInstrumentation instrumentation = new GcsInstrumentation();
   private GcsStorageStatistics storageStatistics;
 

hadoop-tools/hadoop-gcp/src/site/markdown/tools/hadoop-gcp/Configuration.md

@@ -78,7 +78,7 @@
 
   * `UNAUTHENTICATED` - configures unauthenticated access
 
-  * `USER_CREDENTIALS` - configure [user credentials](https://www.google.com/search?q=%23user-credentials)
+  * `USER_CREDENTIALS` - configure [user credentials](#user-credentials)
 
 * `fs.gs.auth.service.account.json.keyfile` (not set by default)
 

hadoop-tools/hadoop-gcp/src/site/markdown/tools/hadoop-gcp/testing.md

@@ -65,7 +65,7 @@ Example:
     </property>
     <property>
       <name>fs.contract.test.fs.gs</name>
-      <value>YOUR_BUCKET_NAME</value>
+      <value>gs://your_bucket</value>
     </property>
 </configuration>
 ```