diff --git a/dev-support/pmd/pmd-ruleset.xml b/dev-support/pmd/pmd-ruleset.xml
index d03a463def62..63371ac20a1d 100644
--- a/dev-support/pmd/pmd-ruleset.xml
+++ b/dev-support/pmd/pmd-ruleset.xml
@@ -45,7 +45,9 @@
   <rule ref="category/java/performance.xml/StringToString"/>
   <rule ref="category/java/performance.xml/UseArraysAsList"/>
   <rule ref="category/java/performance.xml/UseIndexOfChar"/>
+  <rule ref="category/java/performance.xml/UseStringBufferForStringAppends"/>
   <rule ref="category/java/performance.xml/UseStringBufferLength"/>
+  <rule ref="category/java/performance.xml/UselessStringValueOf"/>
 
   <rule ref="category/java/codestyle.xml/FieldDeclarationsShouldBeAtStartOfClass">
     <properties>
diff --git a/hadoop-hdds/cli-common/src/main/java/org/apache/hadoop/hdds/cli/GenericCli.java b/hadoop-hdds/cli-common/src/main/java/org/apache/hadoop/hdds/cli/GenericCli.java
index da46c2600389..6d6463b09406 100644
--- a/hadoop-hdds/cli-common/src/main/java/org/apache/hadoop/hdds/cli/GenericCli.java
+++ b/hadoop-hdds/cli-common/src/main/java/org/apache/hadoop/hdds/cli/GenericCli.java
@@ -134,22 +134,23 @@ protected PrintWriter err() {
   }
 
   private static String handleFileSystemException(FileSystemException e) {
-    String errorMessage = e.getMessage();
+    StringBuilder sb = new StringBuilder();
+    sb.append("Error: ");
 
     // If reason is set, return the exception's message as it is.
     // Otherwise, construct a custom message based on the type of exception
     if (e.getReason() == null) {
       if (e instanceof NoSuchFileException) {
-        errorMessage = "File not found: " + errorMessage;
+        sb.append("File not found: ");
       } else if (e instanceof AccessDeniedException) {
-        errorMessage = "Access denied: " + errorMessage;
+        sb.append("Access denied: ");
       } else if (e instanceof FileAlreadyExistsException) {
-        errorMessage = "File already exists: " + errorMessage;
+        sb.append("File already exists: ");
       } else {
-        errorMessage = e.getClass().getSimpleName() + ": " + errorMessage;
+        sb.append(e.getClass().getSimpleName()).append(": ");
       }
     }
 
-    return "Error: " + errorMessage;
+    return sb.append(e.getMessage()).toString();
   }
 }
diff --git a/hadoop-hdds/client/src/main/java/org/apache/hadoop/hdds/scm/XceiverClientManager.java b/hadoop-hdds/client/src/main/java/org/apache/hadoop/hdds/scm/XceiverClientManager.java
index 629932b0d371..4b9dd57004c3 100644
--- a/hadoop-hdds/client/src/main/java/org/apache/hadoop/hdds/scm/XceiverClientManager.java
+++ b/hadoop-hdds/client/src/main/java/org/apache/hadoop/hdds/scm/XceiverClientManager.java
@@ -163,7 +163,9 @@ protected XceiverClientSpi getClient(Pipeline pipeline, boolean topologyAware)
 
   private String getPipelineCacheKey(Pipeline pipeline,
                                      boolean topologyAware) {
-    String key = pipeline.getId().getId().toString() + pipeline.getType();
+    StringBuilder key = new StringBuilder()
+        .append(pipeline.getId().getId())
+        .append(pipeline.getType());
     boolean isEC = pipeline.getType() == HddsProtos.ReplicationType.EC;
     if (topologyAware || isEC) {
       try {
@@ -183,7 +185,8 @@ private String getPipelineCacheKey(Pipeline pipeline,
         // Standalone port is chosen since all datanodes should have a
         // standalone port regardless of version and this port should not
         // have any collisions.
-        key += closestNode.getHostName() + closestNode.getStandalonePort();
+        key.append(closestNode.getHostName())
+            .append(closestNode.getStandalonePort());
       } catch (IOException e) {
         LOG.error("Failed to get closest node to create pipeline cache key:" +
             e.getMessage());
@@ -194,13 +197,13 @@ private String getPipelineCacheKey(Pipeline pipeline,
       // Append user short name to key to prevent a different user
       // from using same instance of xceiverClient.
       try {
-        key += UserGroupInformation.getCurrentUser().getShortUserName();
+        key.append(UserGroupInformation.getCurrentUser().getShortUserName());
       } catch (IOException e) {
         LOG.error("Failed to get current user to create pipeline cache key:" +
             e.getMessage());
       }
     }
-    return key;
+    return key.toString();
   }
 
   /**
diff --git a/hadoop-hdds/client/src/main/java/org/apache/hadoop/ozone/client/io/ECBlockReconstructedStripeInputStream.java b/hadoop-hdds/client/src/main/java/org/apache/hadoop/ozone/client/io/ECBlockReconstructedStripeInputStream.java
index 73eaa7b74468..c71db0e41ed4 100644
--- a/hadoop-hdds/client/src/main/java/org/apache/hadoop/ozone/client/io/ECBlockReconstructedStripeInputStream.java
+++ b/hadoop-hdds/client/src/main/java/org/apache/hadoop/ozone/client/io/ECBlockReconstructedStripeInputStream.java
@@ -597,13 +597,13 @@ protected void loadDataBuffersFromStream()
       } catch (ExecutionException ee) {
         boolean added = failedDataIndexes.add(index);
         Throwable t = ee.getCause() != null ? ee.getCause() : ee;
-        String msg = "{}: error reading [{}]";
+        StringBuilder msg = new StringBuilder("{}: error reading [{}]");
         if (added) {
-          msg += ", marked as failed";
+          msg.append(", marked as failed");
         } else {
-          msg += ", already had failed"; // should not really happen
+          msg.append(", already had failed"); // should not really happen
         }
-        LOG.info(msg, this, index, t);
+        LOG.info(msg.toString(), this, index, t);
 
         exceptionOccurred = true;
       } catch (InterruptedException ie) {
diff --git a/hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBCheckpointManager.java b/hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBCheckpointManager.java
index 618c9f9b4863..ef21de8c6c9b 100644
--- a/hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBCheckpointManager.java
+++ b/hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBCheckpointManager.java
@@ -62,16 +62,20 @@ public RocksDBCheckpoint createCheckpoint(String parentDir, String name) {
     try {
       long currentTime = System.currentTimeMillis();
 
-      String checkpointDir = StringUtils.EMPTY;
+      StringBuilder checkpointDir = new StringBuilder();
       if (StringUtils.isNotEmpty(checkpointNamePrefix)) {
-        checkpointDir += checkpointNamePrefix;
+        checkpointDir.append(checkpointNamePrefix);
       }
+
       if (name == null) {
-        name = "_" + RDB_CHECKPOINT_DIR_PREFIX + currentTime;
+        checkpointDir.append('_')
+            .append(RDB_CHECKPOINT_DIR_PREFIX)
+            .append(currentTime);
+      } else {
+        checkpointDir.append(name);
       }
-      checkpointDir += name;
 
-      Path checkpointPath = Paths.get(parentDir, checkpointDir);
+      Path checkpointPath = Paths.get(parentDir, checkpointDir.toString());
       Instant start = Instant.now();
 
       // Flush the DB WAL and mem table.
diff --git a/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/nssummary/DiskUsageSubCommand.java b/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/nssummary/DiskUsageSubCommand.java
index 1c4039be18e1..c3277d038beb 100644
--- a/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/nssummary/DiskUsageSubCommand.java
+++ b/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/nssummary/DiskUsageSubCommand.java
@@ -162,13 +162,14 @@ public Void call() throws Exception {
           if (cnt >= limit) {
             break;
           }
-          String subPath = subPathDU.path("path").asText("");
+          StringBuilder sb = new StringBuilder(subPathDU.path("path").asText(""));
           // differentiate key from other types
           if (!subPathDU.path("isKey").asBoolean(false)) {
-            subPath += OM_KEY_PREFIX;
+            sb.append(OM_KEY_PREFIX);
           }
           long size = subPathDU.path("size").asLong(-1);
           long sizeWithReplica = subPathDU.path("sizeWithReplica").asLong(-1);
+          String subPath = sb.toString();
           if (subPath.startsWith(seekStr)) {
             printDURow(subPath, size, sizeWithReplica);
             ++cnt;
diff --git a/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/om/ListOpenFilesSubCommand.java b/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/om/ListOpenFilesSubCommand.java
index c5477e0cb0ec..f261f2579d1b 100644
--- a/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/om/ListOpenFilesSubCommand.java
+++ b/hadoop-ozone/cli-admin/src/main/java/org/apache/hadoop/ozone/admin/om/ListOpenFilesSubCommand.java
@@ -142,40 +142,42 @@ private void printOpenKeysList(ListOpenFilesResult res) {
     for (OpenKeySession e : openFileList) {
       long clientId = e.getId();
       OmKeyInfo omKeyInfo = e.getKeyInfo();
-      String line = clientId + "\t" + Instant.ofEpochMilli(omKeyInfo.getCreationTime()) + "\t";
+      StringBuilder line = new StringBuilder()
+          .append(clientId).append('\t')
+          .append(Instant.ofEpochMilli(omKeyInfo.getCreationTime())).append('\t');
 
       if (omKeyInfo.isHsync()) {
         String hsyncClientIdStr =
             omKeyInfo.getMetadata().get(OzoneConsts.HSYNC_CLIENT_ID);
         long hsyncClientId = Long.parseLong(hsyncClientIdStr);
         if (clientId == hsyncClientId) {
-          line += "Yes\t\t";
+          line.append("Yes\t\t");
         } else {
           // last hsync'ed with a different client ID than the client that
           // initially opens the file (!)
-          line += "Yes w/ cid " + hsyncClientIdStr + "\t";
+          line.append("Yes w/ cid ").append(hsyncClientIdStr).append('\t');
         }
 
         if (showDeleted) {
           if (omKeyInfo.getMetadata().containsKey(OzoneConsts.DELETED_HSYNC_KEY)) {
-            line += "Yes\t\t";
+            line.append("Yes\t\t");
           } else {
-            line += "No\t\t";
+            line.append("No\t\t");
           }
         }
         if (showOverwritten) {
           if (omKeyInfo.getMetadata().containsKey(OzoneConsts.OVERWRITTEN_HSYNC_KEY)) {
-            line += "Yes\t";
+            line.append("Yes\t");
           } else {
-            line += "No\t";
+            line.append("No\t");
           }
         }
       } else {
-        line += showDeleted ? "No\t\tNo\t\t" : "No\t\t";
-        line += showOverwritten ? "No\t" : "";
+        line.append(showDeleted ? "No\t\tNo\t\t" : "No\t\t");
+        line.append(showOverwritten ? "No\t" : "");
       }
 
-      line += getFullPathFromKeyInfo(omKeyInfo);
+      line.append(getFullPathFromKeyInfo(omKeyInfo));
 
       System.out.println(line);
     }
@@ -222,16 +224,16 @@ private String getMessageString(ListOpenFilesResult res, List<OpenKeySession> op
    * @return the command to get the next batch of open keys
    */
   private String getCmdForNextBatch(String lastElementFullPath) {
-    String nextBatchCmd = "ozone admin om lof " + omAddressOptions;
+    StringBuilder nextBatchCmd = new StringBuilder("ozone admin om lof ").append(omAddressOptions);
     if (json) {
-      nextBatchCmd += " --json";
+      nextBatchCmd.append(" --json");
     }
-    nextBatchCmd += " --length=" + limit;
+    nextBatchCmd.append(" --length=").append(limit);
     if (pathPrefix != null && !pathPrefix.isEmpty()) {
-      nextBatchCmd += " --prefix=" + pathPrefix;
+      nextBatchCmd.append(" --prefix=").append(pathPrefix);
     }
-    nextBatchCmd += " --start=" + lastElementFullPath;
-    return nextBatchCmd;
+    nextBatchCmd.append(" --start=").append(lastElementFullPath);
+    return nextBatchCmd.toString();
   }
 
   private String getFullPathFromKeyInfo(OmKeyInfo oki) {
diff --git a/hadoop-ozone/cli-shell/src/main/java/org/apache/hadoop/ozone/shell/keys/ListKeyHandler.java b/hadoop-ozone/cli-shell/src/main/java/org/apache/hadoop/ozone/shell/keys/ListKeyHandler.java
index e5a9f2aa2283..32accb32204f 100644
--- a/hadoop-ozone/cli-shell/src/main/java/org/apache/hadoop/ozone/shell/keys/ListKeyHandler.java
+++ b/hadoop-ozone/cli-shell/src/main/java/org/apache/hadoop/ozone/shell/keys/ListKeyHandler.java
@@ -61,18 +61,18 @@ private void listKeysInsideBucket(OzoneClient client, OzoneAddress address)
     String volumeName = address.getVolumeName();
     String bucketName = address.getBucketName();
     String snapshotNameWithIndicator = address.getSnapshotNameWithIndicator();
-    String keyPrefix = "";
+    StringBuilder keyPrefix = new StringBuilder();
 
     if (!Strings.isNullOrEmpty(snapshotNameWithIndicator)) {
-      keyPrefix += snapshotNameWithIndicator;
+      keyPrefix.append(snapshotNameWithIndicator);
 
       if (!Strings.isNullOrEmpty(prefixFilter.getPrefix())) {
-        keyPrefix += "/";
+        keyPrefix.append('/');
       }
     }
 
     if (!Strings.isNullOrEmpty(prefixFilter.getPrefix())) {
-      keyPrefix += prefixFilter.getPrefix();
+      keyPrefix.append(prefixFilter.getPrefix());
     }
 
     OzoneVolume vol = client.getObjectStore().getVolume(volumeName);
@@ -82,7 +82,7 @@ private void listKeysInsideBucket(OzoneClient client, OzoneAddress address)
       bucket.setListCacheSize(maxKeyLimit);
     }
     Iterator<? extends OzoneKey> keyIterator = bucket.listKeys(
-        keyPrefix, listOptions.getStartItem());
+        keyPrefix.toString(), listOptions.getStartItem());
 
     int counter = printAsJsonArray(keyIterator, maxKeyLimit);
 
diff --git a/hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/request/file/OMFileRequest.java b/hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/request/file/OMFileRequest.java
index 84722ede6294..80de9df1b30e 100644
--- a/hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/request/file/OMFileRequest.java
+++ b/hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/request/file/OMFileRequest.java
@@ -192,7 +192,7 @@ public static OMPathInfoWithFSO verifyDirectoryKeysInPath(
     List<OzoneAcl> acls = omBucketInfo.getAcls();
 
     long lastKnownParentId = omBucketInfo.getObjectID();
-    String dbDirName = ""; // absolute path for trace logs
+    StringBuilder dbDirName = new StringBuilder(); // absolute path for trace logs
     // for better logging
     StringBuilder fullKeyPath = new StringBuilder(bucketKey);
     while (elements.hasNext()) {
@@ -219,7 +219,7 @@ public static OMPathInfoWithFSO verifyDirectoryKeysInPath(
       OmDirectoryInfo omDirInfo = omMetadataManager.getDirectoryTable().
               get(dbNodeName);
       if (omDirInfo != null) {
-        dbDirName += omDirInfo.getName() + OzoneConsts.OZONE_URI_DELIMITER;
+        dbDirName.append(omDirInfo.getName()).append(OzoneConsts.OZONE_URI_DELIMITER);
         if (elements.hasNext()) {
           result = OMDirectoryResult.DIRECTORY_EXISTS_IN_GIVENPATH;
           lastKnownParentId = omDirInfo.getObjectID();
@@ -264,7 +264,7 @@ public static OMPathInfoWithFSO verifyDirectoryKeysInPath(
     }
 
     String dbDirKeyName = omMetadataManager.getOzoneDirKey(volumeName,
-            bucketName, dbDirName);
+        bucketName, dbDirName.toString());
     LOG.trace("Acls from parent {} are : {}", dbDirKeyName, acls);
 
     return new OMPathInfoWithFSO(leafNodeName, lastKnownParentId, missing,
diff --git a/hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/handlers/BucketHandler.java b/hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/handlers/BucketHandler.java
index 38038acb6e17..f260347f31b7 100644
--- a/hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/handlers/BucketHandler.java
+++ b/hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/handlers/BucketHandler.java
@@ -100,15 +100,18 @@ public abstract OmDirectoryInfo getDirInfo(String[] names)
    * @return subpath
    */
   public static String buildSubpath(String path, String nextLevel) {
-    String subpath = path;
-    if (!subpath.startsWith(OM_KEY_PREFIX)) {
-      subpath = OM_KEY_PREFIX + subpath;
-    }
-    subpath = removeTrailingSlashIfNeeded(subpath);
+    path = !path.startsWith(OM_KEY_PREFIX)
+        ? OM_KEY_PREFIX + path
+        : path;
+
+    StringBuilder sb = new StringBuilder(path)
+        .append(removeTrailingSlashIfNeeded(path));
+
     if (nextLevel != null) {
-      subpath = subpath + OM_KEY_PREFIX + nextLevel;
+      sb.append(nextLevel);
     }
-    return subpath;
+
+    return sb.toString();
   }
 
   /**