diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
index 952cf8ba3b0ec..2af24af513b9e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
@@ -43,6 +43,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.command.CancelAllocationCommand;
+import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
@@ -71,12 +72,13 @@
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportService;
 
-import java.io.File;
 import java.io.IOException;
+import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
@@ -1352,15 +1354,12 @@ private String getOlderLuceneCodec() throws IOException {
         final TreeSet<String> codecNames = new TreeSet<>();
         ZipInputStream zip = new ZipInputStream(Codec.class.getProtectionDomain().getCodeSource().getLocation().openStream());
         Pattern pattern = Pattern.compile("lucene[0-9]+");
-        while (true) {
-            ZipEntry e = zip.getNextEntry();
-            if (e == null) break;
-            // Filter lucene codec names from directory
-            if (e.isDirectory()) {
+        for (ZipEntry entry = zip.getNextEntry(); entry != null; entry = zip.getNextEntry()) {
+            if (entry.isDirectory()) {
                 // Remove trailing file separator from path i.e. '../lucene94/' -> '../lucene94'
-                final String dirPath = e.getName().substring(0, e.getName().length() - 1);
+                final String dirPath = entry.getName().substring(0, entry.getName().length() - 1);
                 // Fetch name i.e. '../lucene94' -> 'lucene94'
-                final String dirName = dirPath.substring(dirPath.lastIndexOf(File.separator) + 1);
+                final String dirName = dirPath.substring(dirPath.lastIndexOf(PathUtils.getDefaultFileSystem().getSeparator()) + 1);
                 Matcher matcher = pattern.matcher(dirName);
                 if (matcher.matches()) {
                     codecNames.add(dirName);
@@ -1370,6 +1369,6 @@ private String getOlderLuceneCodec() throws IOException {
         logger.debug("--> Older lucene codecs {}", codecNames);
         String oldestSupportedCodec = codecNames.pollFirst();
         // Get actual lucene codec class name i.e. lucene90 -> Lucene90
-        return oldestSupportedCodec.substring(0, 1).toUpperCase() + oldestSupportedCodec.substring(1);
+        return oldestSupportedCodec.substring(0, 1).toUpperCase(Locale.getDefault()) + oldestSupportedCodec.substring(1);
     }
 }