diff --git a/src/main/java/org/codelibs/fess/api/json/JsonApiManager.java b/src/main/java/org/codelibs/fess/api/json/JsonApiManager.java
index cf669a4c1..14566ee17 100644
--- a/src/main/java/org/codelibs/fess/api/json/JsonApiManager.java
+++ b/src/main/java/org/codelibs/fess/api/json/JsonApiManager.java
@@ -112,7 +112,7 @@ public class JsonApiManager extends BaseApiManager {
     }
 
     protected void processPingRequest(final HttpServletRequest request, final HttpServletResponse response, final FilterChain chain) {
-        final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+        final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
         int status;
         Exception err = null;
         try {
@@ -547,7 +547,7 @@ public class JsonApiManager extends BaseApiManager {
         sb.append(" [ ").append(sw.toString()).append(" ]");
         try {
             sw.close();
-        } catch (IOException ignore) {}
+        } catch (final IOException ignore) {}
         writeJsonResponse(status, body, sb.toString());
     }
 
diff --git a/src/main/java/org/codelibs/fess/app/web/admin/esreq/AdminEsreqAction.java b/src/main/java/org/codelibs/fess/app/web/admin/esreq/AdminEsreqAction.java
index cd158353d..4ea26887f 100644
--- a/src/main/java/org/codelibs/fess/app/web/admin/esreq/AdminEsreqAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/admin/esreq/AdminEsreqAction.java
@@ -111,7 +111,7 @@ public class AdminEsreqAction extends FessAdminAction {
         return redirect(getClass()); // no-op
     }
 
-    private CurlRequest getCurlRequest(String header) {
+    private CurlRequest getCurlRequest(final String header) {
         if (StringUtil.isBlank(header)) {
             return null;
         }
@@ -143,7 +143,7 @@ public class AdminEsreqAction extends FessAdminAction {
         return null;
     }
 
-    private HtmlResponse asListHtml(Runnable runnable) {
+    private HtmlResponse asListHtml(final Runnable runnable) {
         if (runnable != null) {
             runnable.run();
         }
diff --git a/src/main/java/org/codelibs/fess/app/web/admin/upgrade/AdminUpgradeAction.java b/src/main/java/org/codelibs/fess/app/web/admin/upgrade/AdminUpgradeAction.java
index 0a8fb8dfc..e9f0b1e44 100644
--- a/src/main/java/org/codelibs/fess/app/web/admin/upgrade/AdminUpgradeAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/admin/upgrade/AdminUpgradeAction.java
@@ -371,7 +371,7 @@ public class AdminUpgradeAction extends FessAdminAction {
         roleTypeBhv.queryDelete(cb -> {});
 
         roleBhv.selectEntity(cb -> cb.query().setName_Equal("guest")).orElseGet(() -> {
-            Role entity = new Role();
+            final Role entity = new Role();
             entity.setName("guest");
             roleBhv.insert(entity);
             return entity;
@@ -450,7 +450,7 @@ public class AdminUpgradeAction extends FessAdminAction {
                 if (!pmResponse.isAcknowledged()) {
                     logger.warn("Failed to add " + field + " to " + index + "/" + type);
                 }
-            } catch (Exception e) {
+            } catch (final Exception e) {
                 logger.warn("Failed to add " + field + " to " + index + "/" + type, e);
             }
         }
diff --git a/src/main/java/org/codelibs/fess/app/web/base/FessSearchAction.java b/src/main/java/org/codelibs/fess/app/web/base/FessSearchAction.java
index 8a03eb465..b931b6929 100644
--- a/src/main/java/org/codelibs/fess/app/web/base/FessSearchAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/base/FessSearchAction.java
@@ -118,7 +118,7 @@ public abstract class FessSearchAction extends FessBaseAction {
             locale = Locale.ENGLISH;
         }
         runtime.registerData("langItems", systemHelper.getLanguageItems(locale));
-        String username = systemHelper.getUsername();
+        final String username = systemHelper.getUsername();
         runtime.registerData("username", username);
         runtime.registerData("adminUser", fessConfig.isAdminUser(username));
 
diff --git a/src/main/java/org/codelibs/fess/app/web/base/login/FessLoginAssist.java b/src/main/java/org/codelibs/fess/app/web/base/login/FessLoginAssist.java
index 48042beff..b4423f79b 100644
--- a/src/main/java/org/codelibs/fess/app/web/base/login/FessLoginAssist.java
+++ b/src/main/java/org/codelibs/fess/app/web/base/login/FessLoginAssist.java
@@ -144,8 +144,8 @@ public class FessLoginAssist extends TypicalLoginAssist<String, FessUserBean, Fe
     //                                                                      ==============
 
     @Override
-    public HtmlResponse loginRedirect(String account, String password, LoginOpCall opLambda, LoginRedirectSuccessCall oneArgLambda)
-            throws LoginFailureException {
+    public HtmlResponse loginRedirect(final String account, final String password, final LoginOpCall opLambda,
+            final LoginRedirectSuccessCall oneArgLambda) throws LoginFailureException {
         return loginRedirect(new UserPasswordLoginCredential(account, password), opLambda, oneArgLambda);
     }
 
diff --git a/src/main/java/org/codelibs/fess/app/web/base/login/LoginCredential.java b/src/main/java/org/codelibs/fess/app/web/base/login/LoginCredential.java
index 71fb4f65e..891a88393 100644
--- a/src/main/java/org/codelibs/fess/app/web/base/login/LoginCredential.java
+++ b/src/main/java/org/codelibs/fess/app/web/base/login/LoginCredential.java
@@ -22,16 +22,16 @@ public interface LoginCredential {
 
     Object getResource();
 
-    public default void assertLoginAccountRequired(String account) {
+    public default void assertLoginAccountRequired(final String account) {
         if (account == null || account.length() == 0) {
-            String msg = "The argument 'account' should not be null for login.";
+            final String msg = "The argument 'account' should not be null for login.";
             throw new IllegalArgumentException(msg);
         }
     }
 
-    public default void assertLoginPasswordRequired(String password) {
+    public default void assertLoginPasswordRequired(final String password) {
         if (password == null || password.length() == 0) {
-            String msg = "The argument 'password' should not be null for login.";
+            final String msg = "The argument 'password' should not be null for login.";
             throw new IllegalArgumentException(msg);
         }
     }
diff --git a/src/main/java/org/codelibs/fess/app/web/base/login/SSOLoginCredential.java b/src/main/java/org/codelibs/fess/app/web/base/login/SSOLoginCredential.java
index e1e963613..ab46869ee 100644
--- a/src/main/java/org/codelibs/fess/app/web/base/login/SSOLoginCredential.java
+++ b/src/main/java/org/codelibs/fess/app/web/base/login/SSOLoginCredential.java
@@ -18,7 +18,7 @@ package org.codelibs.fess.app.web.base.login;
 import org.dbflute.util.DfCollectionUtil;
 
 public class SSOLoginCredential implements LoginCredential {
-    private String username;
+    private final String username;
 
     // private Principal principal;
 
diff --git a/src/main/java/org/codelibs/fess/app/web/base/login/UserPasswordLoginCredential.java b/src/main/java/org/codelibs/fess/app/web/base/login/UserPasswordLoginCredential.java
index 67d06a438..39763ce3e 100644
--- a/src/main/java/org/codelibs/fess/app/web/base/login/UserPasswordLoginCredential.java
+++ b/src/main/java/org/codelibs/fess/app/web/base/login/UserPasswordLoginCredential.java
@@ -18,8 +18,8 @@ package org.codelibs.fess.app.web.base.login;
 import org.dbflute.util.DfCollectionUtil;
 
 public class UserPasswordLoginCredential implements LoginCredential {
-    private String username;
-    private String password;
+    private final String username;
+    private final String password;
 
     public UserPasswordLoginCredential(final String username, final String password) {
         this.username = username;
diff --git a/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java b/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java
index 6638eb809..077588de1 100644
--- a/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/cache/CacheForm.java
@@ -23,7 +23,6 @@ import javax.validation.constraints.Size;
 import org.lastaflute.web.validation.Required;
 
 public class CacheForm {
-    private static final long serialVersionUID = 1L;
 
     @Required
     @Size(max = 100)
diff --git a/src/main/java/org/codelibs/fess/app/web/error/ErrorForm.java b/src/main/java/org/codelibs/fess/app/web/error/ErrorForm.java
index 5ac1cdd52..3fa9f1503 100644
--- a/src/main/java/org/codelibs/fess/app/web/error/ErrorForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/error/ErrorForm.java
@@ -20,8 +20,6 @@ import java.util.Map;
 
 public class ErrorForm {
 
-    private static final long serialVersionUID = 1L;
-
     public Map<String, String[]> fields = new HashMap<>();
 
     public String q;
diff --git a/src/main/java/org/codelibs/fess/app/web/login/LoginForm.java b/src/main/java/org/codelibs/fess/app/web/login/LoginForm.java
index b74da51e8..56105bf9a 100644
--- a/src/main/java/org/codelibs/fess/app/web/login/LoginForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/login/LoginForm.java
@@ -18,7 +18,6 @@ package org.codelibs.fess.app.web.login;
 import org.hibernate.validator.constraints.NotBlank;
 
 public class LoginForm {
-    private static final long serialVersionUID = 1L;
 
     @NotBlank
     public String username;
diff --git a/src/main/java/org/codelibs/fess/app/web/profile/ProfileForm.java b/src/main/java/org/codelibs/fess/app/web/profile/ProfileForm.java
index 7ffc933ae..4213fbe02 100644
--- a/src/main/java/org/codelibs/fess/app/web/profile/ProfileForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/profile/ProfileForm.java
@@ -22,7 +22,6 @@ package org.codelibs.fess.app.web.profile;
 import org.hibernate.validator.constraints.NotBlank;
 
 public class ProfileForm {
-    private static final long serialVersionUID = 1L;
 
     @NotBlank
     public String oldPassword;
diff --git a/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java b/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java
index 96abe2229..c595d6ef2 100644
--- a/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/screenshot/ScreenshotForm.java
@@ -23,7 +23,6 @@ import javax.validation.constraints.Size;
 import org.lastaflute.web.validation.Required;
 
 public class ScreenshotForm {
-    private static final long serialVersionUID = 1L;
 
     @Required
     @Size(max = 100)
diff --git a/src/main/java/org/codelibs/fess/crawler/FessCrawlerThread.java b/src/main/java/org/codelibs/fess/crawler/FessCrawlerThread.java
index 31f9158bd..413d359fe 100644
--- a/src/main/java/org/codelibs/fess/crawler/FessCrawlerThread.java
+++ b/src/main/java/org/codelibs/fess/crawler/FessCrawlerThread.java
@@ -66,7 +66,7 @@ public class FessCrawlerThread extends CrawlerThread {
             final CrawlingInfoHelper crawlingInfoHelper = ComponentUtil.getCrawlingInfoHelper();
             final SambaHelper sambaHelper = ComponentUtil.getSambaHelper();
             final IndexingHelper indexingHelper = ComponentUtil.getIndexingHelper();
-            final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+            final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
 
             final String url = urlQueue.getUrl();
             ResponseData responseData = null;
diff --git a/src/main/java/org/codelibs/fess/dict/mapping/CharMappingFile.java b/src/main/java/org/codelibs/fess/dict/mapping/CharMappingFile.java
index ae365a534..e89da2334 100644
--- a/src/main/java/org/codelibs/fess/dict/mapping/CharMappingFile.java
+++ b/src/main/java/org/codelibs/fess/dict/mapping/CharMappingFile.java
@@ -60,7 +60,7 @@ public class CharMappingFile extends DictionaryFile<CharMappingItem> {
     }
 
     @Override
-    public OptionalEntity<CharMappingItem> get(long id) {
+    public OptionalEntity<CharMappingItem> get(final long id) {
         if (mappingItemList == null) {
             reload(null, null);
         }
@@ -137,7 +137,7 @@ public class CharMappingFile extends DictionaryFile<CharMappingItem> {
                 String[] inputs;
                 String output;
 
-                Matcher m = parsePattern.matcher(line.trim());
+                final Matcher m = parsePattern.matcher(line.trim());
 
                 if (!m.find()) {
                     throw new DictionaryException("Failed to parse " + path);
diff --git a/src/main/java/org/codelibs/fess/ds/impl/FileListIndexUpdateCallbackImpl.java b/src/main/java/org/codelibs/fess/ds/impl/FileListIndexUpdateCallbackImpl.java
index f23b023b6..2d6d14012 100644
--- a/src/main/java/org/codelibs/fess/ds/impl/FileListIndexUpdateCallbackImpl.java
+++ b/src/main/java/org/codelibs/fess/ds/impl/FileListIndexUpdateCallbackImpl.java
@@ -182,7 +182,7 @@ public class FileListIndexUpdateCallbackImpl implements IndexUpdateCallback, Aut
             deleteIdList.add(ComponentUtil.getCrawlingInfoHelper().generateId(dataMap));
 
             if (deleteIdList.size() >= maxDeleteDocumentCacheSize) {
-                final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+                final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
                 final IndexingHelper indexingHelper = ComponentUtil.getIndexingHelper();
                 for (final String id : deleteIdList) {
                     indexingHelper.deleteDocument(fessEsClient, id);
@@ -200,7 +200,7 @@ public class FileListIndexUpdateCallbackImpl implements IndexUpdateCallback, Aut
     @Override
     public void commit() {
         if (!deleteIdList.isEmpty()) {
-            final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+            final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
             final IndexingHelper indexingHelper = ComponentUtil.getIndexingHelper();
             for (final String id : deleteIdList) {
                 indexingHelper.deleteDocument(fessEsClient, id);
diff --git a/src/main/java/org/codelibs/fess/ds/impl/IndexUpdateCallbackImpl.java b/src/main/java/org/codelibs/fess/ds/impl/IndexUpdateCallbackImpl.java
index 17a1935a6..f284f8a02 100644
--- a/src/main/java/org/codelibs/fess/ds/impl/IndexUpdateCallbackImpl.java
+++ b/src/main/java/org/codelibs/fess/ds/impl/IndexUpdateCallbackImpl.java
@@ -57,7 +57,7 @@ public class IndexUpdateCallbackImpl implements IndexUpdateCallback {
     public void store(final Map<String, String> paramMap, final Map<String, Object> dataMap) {
         final long startTime = System.currentTimeMillis();
         final FessConfig fessConfig = ComponentUtil.getFessConfig();
-        final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+        final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
 
         if (logger.isDebugEnabled()) {
             logger.debug("Adding " + dataMap);
@@ -119,7 +119,7 @@ public class IndexUpdateCallbackImpl implements IndexUpdateCallback {
         synchronized (docList) {
             if (!docList.isEmpty()) {
                 final IndexingHelper indexingHelper = ComponentUtil.getIndexingHelper();
-                final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+                final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
                 indexingHelper.sendDocuments(fessEsClient, docList);
             }
         }
diff --git a/src/main/java/org/codelibs/fess/exception/ServletRuntimeException.java b/src/main/java/org/codelibs/fess/exception/ServletRuntimeException.java
index d784ec977..d6c8b96f8 100644
--- a/src/main/java/org/codelibs/fess/exception/ServletRuntimeException.java
+++ b/src/main/java/org/codelibs/fess/exception/ServletRuntimeException.java
@@ -21,7 +21,7 @@ public class ServletRuntimeException extends RuntimeException {
 
     private static final long serialVersionUID = 1L;
 
-    public ServletRuntimeException(ServletException e) {
+    public ServletRuntimeException(final ServletException e) {
         super(e);
     }
 
diff --git a/src/main/java/org/codelibs/fess/filter/SpnegoFilter.java b/src/main/java/org/codelibs/fess/filter/SpnegoFilter.java
index 136fb9f09..2b774e696 100644
--- a/src/main/java/org/codelibs/fess/filter/SpnegoFilter.java
+++ b/src/main/java/org/codelibs/fess/filter/SpnegoFilter.java
@@ -42,6 +42,7 @@ import org.codelibs.spnego.SpnegoHttpServletRequest;
  */
 public class SpnegoFilter extends SpnegoHttpFilter {
 
+    @Override
     public void init(final FilterConfig filterConfig) throws ServletException {
         ComponentUtil.processAfterContainerInit(() -> {
             if (ComponentUtil.getFessConfig().isSsoEnabled()) {
@@ -65,7 +66,7 @@ public class SpnegoFilter extends SpnegoHttpFilter {
                 }
 
                 @Override
-                public String getInitParameter(String name) {
+                public String getInitParameter(final String name) {
                     if (Constants.KRB5_CONF.equals(name)) {
                         final String krb5Conf = ComponentUtil.getFessConfig().getSpnegoKrb5Conf();
                         if (StringUtil.isNotBlank(krb5Conf)) {
@@ -125,19 +126,19 @@ public class SpnegoFilter extends SpnegoHttpFilter {
             throws IOException, ServletException {
         if (StringUtil.isNotBlank(request.getRemoteUser())) {
             // TODO save path and parameters into session
-            RequestDispatcher dispatcher = request.getRequestDispatcher(ComponentUtil.getFessConfig().getSsoLoginPath());
+            final RequestDispatcher dispatcher = request.getRequestDispatcher(ComponentUtil.getFessConfig().getSsoLoginPath());
             dispatcher.forward(request, response);
         } else {
             chain.doFilter(request, response);
         }
     }
 
-    protected void doFilter(DoFilterCallback callback) {
+    protected void doFilter(final DoFilterCallback callback) {
         try {
             callback.run();
-        } catch (IOException e) {
+        } catch (final IOException e) {
             throw new IORuntimeException(e);
-        } catch (ServletException e) {
+        } catch (final ServletException e) {
             throw new ServletRuntimeException(e);
         }
     }
diff --git a/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java b/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java
index 3ba250a68..581293d59 100644
--- a/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java
@@ -258,8 +258,8 @@ public class DataIndexHelper {
                                     .should(QueryBuilders.missingQuery(fessConfig.getIndexFieldExpires())))
                             .mustNot(QueryBuilders.termQuery(fessConfig.getIndexFieldSegment(), sessionId));
             try {
-                ComponentUtil.getElasticsearchClient().deleteByQuery(fessConfig.getIndexDocumentUpdateIndex(),
-                        fessConfig.getIndexDocumentType(), queryBuilder);
+                ComponentUtil.getFessEsClient().deleteByQuery(fessConfig.getIndexDocumentUpdateIndex(), fessConfig.getIndexDocumentType(),
+                        queryBuilder);
             } catch (final Exception e) {
                 logger.error("Could not delete old docs at " + dataConfig, e);
             }
diff --git a/src/main/java/org/codelibs/fess/helper/DocumentHelper.java b/src/main/java/org/codelibs/fess/helper/DocumentHelper.java
index bb80d09ad..96caf1864 100644
--- a/src/main/java/org/codelibs/fess/helper/DocumentHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/DocumentHelper.java
@@ -26,8 +26,6 @@ import org.codelibs.fess.util.ComponentUtil;
 
 public class DocumentHelper {
 
-    private static final long serialVersionUID = 1L;
-
     public String getContent(final ResponseData responseData, final String content, final Map<String, Object> dataMap) {
         if (content == null) {
             return StringUtil.EMPTY; // empty
diff --git a/src/main/java/org/codelibs/fess/helper/DuplicateHostHelper.java b/src/main/java/org/codelibs/fess/helper/DuplicateHostHelper.java
index 1e1dee5ca..2f443d46b 100644
--- a/src/main/java/org/codelibs/fess/helper/DuplicateHostHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/DuplicateHostHelper.java
@@ -26,8 +26,6 @@ import org.codelibs.fess.util.ComponentUtil;
 
 public class DuplicateHostHelper {
 
-    private static final long serialVersionUID = 1L;
-
     protected List<DuplicateHost> duplicateHostList;
 
     @PostConstruct
diff --git a/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java b/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java
index c1a6c0533..1354a52b9 100644
--- a/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java
@@ -86,7 +86,7 @@ public class KeyMatchHelper {
     }
 
     protected List<Map<String, Object>> getDocumentList(final KeyMatch keyMatch) {
-        final FessEsClient fessEsClient = ComponentUtil.getElasticsearchClient();
+        final FessEsClient fessEsClient = ComponentUtil.getFessEsClient();
         final FessConfig fessConfig = ComponentUtil.getFessConfig();
         final List<Map<String, Object>> documentList =
                 fessEsClient.getDocumentList(
diff --git a/src/main/java/org/codelibs/fess/helper/LabelTypeHelper.java b/src/main/java/org/codelibs/fess/helper/LabelTypeHelper.java
index 9ade4d75e..59a72a2f1 100644
--- a/src/main/java/org/codelibs/fess/helper/LabelTypeHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/LabelTypeHelper.java
@@ -171,7 +171,7 @@ public class LabelTypeHelper {
             return permissions;
         }
 
-        public void setPermissions(String[] permissions) {
+        public void setPermissions(final String[] permissions) {
             this.permissions = permissions;
         }
     }
diff --git a/src/main/java/org/codelibs/fess/helper/PathMappingHelper.java b/src/main/java/org/codelibs/fess/helper/PathMappingHelper.java
index e7f18489f..8e25d45ad 100644
--- a/src/main/java/org/codelibs/fess/helper/PathMappingHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/PathMappingHelper.java
@@ -32,8 +32,6 @@ import org.slf4j.LoggerFactory;
 
 public class PathMappingHelper {
 
-    private static final long serialVersionUID = 1L;
-
     private static final Logger logger = LoggerFactory.getLogger(PathMappingHelper.class);
 
     private final Map<String, List<PathMapping>> pathMappingMap = new HashMap<>();
diff --git a/src/main/java/org/codelibs/fess/helper/SystemHelper.java b/src/main/java/org/codelibs/fess/helper/SystemHelper.java
index cdc2ba16d..9e5ad4be7 100644
--- a/src/main/java/org/codelibs/fess/helper/SystemHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/SystemHelper.java
@@ -58,8 +58,6 @@ import com.ibm.icu.util.ULocale;
 public class SystemHelper {
     private static final Logger logger = LoggerFactory.getLogger(SystemHelper.class);
 
-    private static final long serialVersionUID = 1L;
-
     protected final Map<String, String> designJspFileNameMap = new HashMap<>();
 
     protected final AtomicBoolean forceStop = new AtomicBoolean(false);
diff --git a/src/main/java/org/codelibs/fess/helper/ViewHelper.java b/src/main/java/org/codelibs/fess/helper/ViewHelper.java
index 2bbfe4509..2db53d841 100644
--- a/src/main/java/org/codelibs/fess/helper/ViewHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/ViewHelper.java
@@ -88,8 +88,6 @@ public class ViewHelper {
 
     private static final Pattern SHARED_FOLDER_PATTERN = Pattern.compile("^file:/+[^/]\\.");
 
-    private static final long serialVersionUID = 1L;
-
     private static final Logger logger = LoggerFactory.getLogger(ViewHelper.class);
 
     @Resource
diff --git a/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java b/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java
index 6b4c5641c..029e5d3ed 100644
--- a/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java
@@ -47,8 +47,6 @@ import org.slf4j.LoggerFactory;
 
 public class WebFsIndexHelper {
 
-    private static final long serialVersionUID = 1L;
-
     private static final Logger logger = LoggerFactory.getLogger(WebFsIndexHelper.class);
 
     @Resource
diff --git a/src/main/java/org/codelibs/fess/util/ComponentUtil.java b/src/main/java/org/codelibs/fess/util/ComponentUtil.java
index 6bd6469c0..6495facbb 100644
--- a/src/main/java/org/codelibs/fess/util/ComponentUtil.java
+++ b/src/main/java/org/codelibs/fess/util/ComponentUtil.java
@@ -147,8 +147,6 @@ public final class ComponentUtil {
 
     private static final String INDEXING_HELPER = "indexingHelper";
 
-    private static final String ELASTICSEARCH_CLIENT = FESS_ES_CLIENT;
-
     private static IndexingHelper indexingHelper;
 
     private static CrawlingConfigHelper crawlingConfigHelper;
@@ -162,7 +160,7 @@ public final class ComponentUtil {
     private ComponentUtil() {
     }
 
-    public static void processAfterContainerInit(Runnable process) {
+    public static void processAfterContainerInit(final Runnable process) {
         if (available()) {
             process.run();
         } else {
@@ -170,7 +168,7 @@ public final class ComponentUtil {
         }
     }
 
-    public static void doInitProcesses(Consumer<? super Runnable> action) {
+    public static void doInitProcesses(final Consumer<? super Runnable> action) {
         try {
             initProcesses.forEach(action);
         } finally {
@@ -299,10 +297,6 @@ public final class ComponentUtil {
         return getComponent(USER_INFO_HELPER);
     }
 
-    public static FessEsClient getElasticsearchClient() {
-        return getComponent(ELASTICSEARCH_CLIENT);
-    }
-
     public static MessageManager getMessageManager() {
         return getComponent(MESSAGE_MANAGER);
     }