Address Viraj's comments

Author: Sanjeet Malhotra

.gitignore

@@ -25,3 +25,4 @@ linklint/
 **/*.log
 tmp
 **/.flattened-pom.xml
+.vscode/

hbase-client/src/main/java/org/apache/hadoop/hbase/client/metrics/ScanMetrics.java

@@ -95,6 +95,12 @@ public class ScanMetrics extends ServerSideScanMetrics {
    */
   public final AtomicLong countOfRemoteRPCRetries = createCounter(REMOTE_RPC_RETRIES_METRIC_NAME);
 
+  /**
+   * Constructor
+   */
+  public ScanMetrics() {
+  }
+
   @Override
   public void moveToNextRegion() {
     super.moveToNextRegion();

hbase-client/src/main/java/org/apache/hadoop/hbase/client/metrics/ScanMetricsRegionInfo.java

@@ -21,6 +21,7 @@
 import org.apache.commons.lang3.builder.HashCodeBuilder;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.yetus.audience.InterfaceAudience;
+import org.apache.yetus.audience.InterfaceStability;
 
 /**
  * POJO for capturing region level details when region level scan metrics are enabled. <br>
@@ -33,6 +34,7 @@
  * {@link ServerSideScanMetrics#collectMetricsByRegion(boolean)}.
  */
 @InterfaceAudience.Public
+@InterfaceStability.Evolving
 public class ScanMetricsRegionInfo {
   /**
    * Users should only compare against this constant by reference and should not make any

hbase-client/src/main/java/org/apache/hadoop/hbase/client/metrics/ScanMetricsUtil.java

@@ -38,28 +38,36 @@ static AtomicLong createCounter(Map<String, AtomicLong> counters, String counter
     return c;
   }
 
-  /** Sets counter with counterName to passed in value, does nothing if counter does not exist. */
+  /**
+   * Sets counter with counterName to passed in value, does nothing if counter does not exist.
+   */
   static void setCounter(Map<String, AtomicLong> counters, String counterName, long value) {
     AtomicLong c = counters.get(counterName);
     if (c != null) {
       c.set(value);
     }
   }
 
-  /** Increments the counter with counterName by delta, does nothing if counter does not exist. */
+  /**
+   * Increments the counter with counterName by delta, does nothing if counter does not exist.
+   */
   static void addToCounter(Map<String, AtomicLong> counters, String counterName, long delta) {
     AtomicLong c = counters.get(counterName);
     if (c != null) {
       c.addAndGet(delta);
     }
   }
 
-  /** Returns true if a counter exists with the counterName */
+  /**
+   * Returns true if a counter exists with the counterName.
+   */
   static boolean hasCounter(Map<String, AtomicLong> counters, String counterName) {
     return counters.containsKey(counterName);
   }
 
-  /** Returns {@link AtomicLong} instance for this counter name, null if counter does not exist. */
+  /**
+   * Returns {@link AtomicLong} instance for this counter name, null if counter does not exist.
+   */
   static AtomicLong getCounter(Map<String, AtomicLong> counters, String counterName) {
     return counters.get(counterName);
   }