diff --git a/src/main/java/org/codelibs/fess/entity/DataStoreParams.java b/src/main/java/org/codelibs/fess/entity/DataStoreParams.java
index d9bac9769..575052aee 100644
--- a/src/main/java/org/codelibs/fess/entity/DataStoreParams.java
+++ b/src/main/java/org/codelibs/fess/entity/DataStoreParams.java
@@ -74,10 +74,9 @@ public class DataStoreParams {
     }
 
     protected static Map<String, Object> getDataMap(final Map<String, Object> params) {
-        if (params instanceof ParamMap<String, Object> paramMap) {
+        if (params instanceof final ParamMap<String, Object> paramMap) {
             return paramMap.getParent();
-        } else {
-            return params;
         }
+        return params;
     }
 }
diff --git a/src/main/java/org/codelibs/fess/es/client/SearchEngineClient.java b/src/main/java/org/codelibs/fess/es/client/SearchEngineClient.java
index a92ff6cad..8a320b6f6 100644
--- a/src/main/java/org/codelibs/fess/es/client/SearchEngineClient.java
+++ b/src/main/java/org/codelibs/fess/es/client/SearchEngineClient.java
@@ -1802,22 +1802,22 @@ public class SearchEngineClient implements Client {
     }
 
     @Override
-    public void createPit(CreatePitRequest createPITRequest, ActionListener<CreatePitResponse> listener) {
+    public void createPit(final CreatePitRequest createPITRequest, final ActionListener<CreatePitResponse> listener) {
         client.createPit(createPITRequest, listener);
     }
 
     @Override
-    public void deletePits(DeletePitRequest deletePITRequest, ActionListener<DeletePitResponse> listener) {
+    public void deletePits(final DeletePitRequest deletePITRequest, final ActionListener<DeletePitResponse> listener) {
         client.deletePits(deletePITRequest, listener);
     }
 
     @Override
-    public void getAllPits(GetAllPitNodesRequest getAllPitNodesRequest, ActionListener<GetAllPitNodesResponse> listener) {
+    public void getAllPits(final GetAllPitNodesRequest getAllPitNodesRequest, final ActionListener<GetAllPitNodesResponse> listener) {
         client.getAllPits(getAllPitNodesRequest, listener);
     }
 
     @Override
-    public void pitSegments(PitSegmentsRequest pitSegmentsRequest, ActionListener<IndicesSegmentResponse> listener) {
+    public void pitSegments(final PitSegmentsRequest pitSegmentsRequest, final ActionListener<IndicesSegmentResponse> listener) {
         client.pitSegments(pitSegmentsRequest, listener);
     }
 }
diff --git a/src/main/java/org/codelibs/fess/util/ErrorToWarnRewritePolicy.java b/src/main/java/org/codelibs/fess/util/ErrorToWarnRewritePolicy.java
index 2bbefa0da..b4a03ea50 100644
--- a/src/main/java/org/codelibs/fess/util/ErrorToWarnRewritePolicy.java
+++ b/src/main/java/org/codelibs/fess/util/ErrorToWarnRewritePolicy.java
@@ -31,17 +31,17 @@ public class ErrorToWarnRewritePolicy implements RewritePolicy {
 
     private final String[] loggerNames;
 
-    public ErrorToWarnRewritePolicy(String[] loggerNames) {
+    public ErrorToWarnRewritePolicy(final String[] loggerNames) {
         this.loggerNames = loggerNames;
     }
 
     @Override
-    public LogEvent rewrite(LogEvent event) {
+    public LogEvent rewrite(final LogEvent event) {
         final String loggerName = event.getLoggerName();
         if (loggerName == null) {
             return event;
         }
-        for (String name : loggerNames) {
+        for (final String name : loggerNames) {
             if (loggerName.startsWith(name)) {
                 final Level sourceLevel = event.getLevel();
                 if (sourceLevel != Level.ERROR) {
@@ -55,7 +55,7 @@ public class ErrorToWarnRewritePolicy implements RewritePolicy {
 
     @PluginFactory
     public static ErrorToWarnRewritePolicy createPolicy(@PluginAttribute("loggers") final String loggerNamePrefix) {
-        String[] loggerNames = loggerNamePrefix != null
+        final String[] loggerNames = loggerNamePrefix != null
                 ? Arrays.stream(loggerNamePrefix.split(",")).map(String::trim).filter(s -> s.length() > 0).toArray(n -> new String[n])
                 : new String[0];
         return new ErrorToWarnRewritePolicy(loggerNames);