diff --git a/src/main/java/org/codelibs/fess/api/json/SearchApiManager.java b/src/main/java/org/codelibs/fess/api/json/SearchApiManager.java
index 415df554a..23696b105 100644
--- a/src/main/java/org/codelibs/fess/api/json/SearchApiManager.java
+++ b/src/main/java/org/codelibs/fess/api/json/SearchApiManager.java
@@ -120,8 +120,7 @@ protected FormatType detectFormatType(final HttpServletRequest request) {
             return FormatType.SEARCH;
         }
         final String type = value.toLowerCase(Locale.ROOT);
-        switch (type) {
-        case "documents":
+        if ("documents".equals(type)) {
             if (values.length > 5 && "favorite".equals(values[5])) {
                 request.setAttribute(DOC_ID_FIELD, values[4]);
                 return FormatType.FAVORITE;
@@ -130,18 +129,21 @@ protected FormatType detectFormatType(final HttpServletRequest request) {
                 return FormatType.SCROLL;
             }
             return FormatType.SEARCH;
-        case "labels":
+        }
+        if ("labels".equals(type)) {
             return FormatType.LABEL;
-        case "popular-words":
+        }
+        if ("popular-words".equals(type)) {
             return FormatType.POPULARWORD;
-        case "favorites":
+        }
+        if ("favorites".equals(type)) {
             return FormatType.FAVORITES;
-        case "health":
+        }
+        if ("health".equals(type)) {
             return FormatType.PING;
-        case "suggest-words":
+        }
+        if ("suggest-words".equals(type)) {
             return FormatType.SUGGEST;
-        default:
-            break;
         }
         // default
         return FormatType.OTHER;
diff --git a/src/main/java/org/codelibs/fess/app/web/admin/backup/AdminBackupAction.java b/src/main/java/org/codelibs/fess/app/web/admin/backup/AdminBackupAction.java
index ca2a8abf3..b238a07d1 100644
--- a/src/main/java/org/codelibs/fess/app/web/admin/backup/AdminBackupAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/admin/backup/AdminBackupAction.java
@@ -319,17 +319,17 @@ public ActionResponse download(final String id) {
             }
             if (id.endsWith(NDJSON_EXTENTION)) {
                 final String name = id.substring(0, id.length() - NDJSON_EXTENTION.length());
-                switch (name) {
-                case "search_log":
+                if ("search_log".equals(name)) {
                     return writeNdjsonResponse(id, getSearchLogNdjsonWriteCall());
-                case "user_info":
+                }
+                if ("user_info".equals(name)) {
                     return writeNdjsonResponse(id, getUserInfoNdjsonWriteCall());
-                case "click_log":
+                }
+                if ("click_log".equals(name)) {
                     return writeNdjsonResponse(id, getClickLogNdjsonWriteCall());
-                case "favorite_log":
+                }
+                if ("favorite_log".equals(name)) {
                     return writeNdjsonResponse(id, getFavoriteLogNdjsonWriteCall());
-                default:
-                    break;
                 }
             } else if ("fess.json".equals(id)) {
                 return asStream(id).contentTypeOctetStream().stream(out -> {
diff --git a/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java b/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java
index ca520826d..9b9c6ac4e 100644
--- a/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/admin/scheduler/AdminSchedulerAction.java
@@ -144,18 +144,12 @@ public HtmlResponse createnewjob(final String type, final String id, final Strin
                 final String decodedName = new String(Base64.getUrlDecoder().decode(name), Constants.CHARSET_UTF_8);
                 scheduledJobForm.name = MessageFormat.format(fessConfig.getJobTemplateTitle(type), decodedName);
                 final String[] ids = { "", "", "" };
-                switch (type) {
-                case Constants.WEB_CRAWLER_TYPE:
+                if (Constants.WEB_CRAWLER_TYPE.equals(type)) {
                     ids[0] = "\"" + id + "\"";
-                    break;
-                case Constants.FILE_CRAWLER_TYPE:
+                } else if (Constants.FILE_CRAWLER_TYPE.equals(type)) {
                     ids[1] = "\"" + id + "\"";
-                    break;
-                case Constants.DATA_CRAWLER_TYPE:
+                } else if (Constants.DATA_CRAWLER_TYPE.equals(type)) {
                     ids[2] = "\"" + id + "\"";
-                    break;
-                default:
-                    break;
                 }
                 scheduledJobForm.scriptData =
                         MessageFormat.format(fessConfig.getJobTemplateScript(), ids[0], ids[1], ids[2], id.replace('-', '_'));
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 993441aa9..7d0b3967d 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
@@ -191,8 +191,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
         validate(form, messages -> {}, this::asIndexHtml);
         verifyToken(this::asIndexHtml);
 
-        switch (form.targetVersion) {
-        case VERSION_13_0:
+        if (VERSION_13_0.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_0();
                 upgradeFrom13_1();
@@ -237,8 +236,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_0, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_1:
+        } else if (VERSION_13_1.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_1();
                 upgradeFrom13_2();
@@ -283,8 +281,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_1, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_2:
+        } else if (VERSION_13_2.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_2();
                 upgradeFrom13_3();
@@ -328,8 +325,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_2, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_3:
+        } else if (VERSION_13_3.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_3();
                 upgradeFrom13_4();
@@ -372,8 +368,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_3, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_4:
+        } else if (VERSION_13_4.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_4();
                 upgradeFrom13_5();
@@ -415,8 +410,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_4, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_5:
+        } else if (VERSION_13_5.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_5();
                 upgradeFrom13_6();
@@ -457,8 +451,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_5, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_6:
+        } else if (VERSION_13_6.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_6();
                 upgradeFrom13_7();
@@ -498,8 +491,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_6, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_7:
+        } else if (VERSION_13_7.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_7();
                 upgradeFrom13_8();
@@ -538,8 +530,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_7, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_8:
+        } else if (VERSION_13_8.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_8();
                 upgradeFrom13_9();
@@ -577,8 +568,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_8, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_9:
+        } else if (VERSION_13_9.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_9();
                 upgradeFrom13_10();
@@ -615,8 +605,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_9, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_10:
+        } else if (VERSION_13_10.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_10();
                 upgradeFrom13_11();
@@ -652,8 +641,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_10, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_11:
+        } else if (VERSION_13_11.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_11();
                 upgradeFrom13_12();
@@ -687,8 +675,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_11, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_12:
+        } else if (VERSION_13_12.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_12();
                 upgradeFrom13_13();
@@ -721,8 +708,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_12, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_13:
+        } else if (VERSION_13_13.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_13();
                 upgradeFrom13_14();
@@ -754,8 +740,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_13, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_14:
+        } else if (VERSION_13_14.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_14();
                 upgradeFrom13_15();
@@ -786,8 +771,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_14, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_15:
+        } else if (VERSION_13_15.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_15();
                 upgradeFrom13_16();
@@ -818,8 +802,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_15, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_16:
+        } else if (VERSION_13_16.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_16();
                 upgradeFrom13_17();
@@ -849,8 +832,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_16, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_13_17:
+        } else if (VERSION_13_17.equals(form.targetVersion)) {
             try {
                 upgradeFrom13_17();
                 upgradeFrom14_0();
@@ -879,8 +861,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_13_17, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_0:
+        } else if (VERSION_14_0.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_0();
                 upgradeFrom14_1();
@@ -908,8 +889,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_0, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_1:
+        } else if (VERSION_14_1.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_1();
                 upgradeFrom14_2();
@@ -936,8 +916,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_1, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_2:
+        } else if (VERSION_14_2.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_2();
                 upgradeFrom14_3();
@@ -963,8 +942,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_2, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_3:
+        } else if (VERSION_14_3.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_3();
                 upgradeFrom14_4();
@@ -989,8 +967,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_3, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_4:
+        } else if (VERSION_14_4.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_4();
                 upgradeFrom14_5();
@@ -1014,8 +991,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_4, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_5:
+        } else if (VERSION_14_5.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_5();
                 upgradeFrom14_6();
@@ -1038,8 +1014,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_5, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_6:
+        } else if (VERSION_14_6.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_6();
                 upgradeFrom14_7();
@@ -1061,8 +1036,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_6, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_7:
+        } else if (VERSION_14_7.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_7();
                 upgradeFrom14_8();
@@ -1083,8 +1057,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_7, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_8:
+        } else if (VERSION_14_8.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_8();
                 upgradeFrom14_9();
@@ -1104,8 +1077,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_8, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_9:
+        } else if (VERSION_14_9.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_9();
                 upgradeFrom14_10();
@@ -1124,8 +1096,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_9, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_10:
+        } else if (VERSION_14_10.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_10();
                 upgradeFrom14_11();
@@ -1143,8 +1114,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_10, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_11:
+        } else if (VERSION_14_11.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_11();
                 upgradeFrom14_12();
@@ -1161,8 +1131,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_11, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_12:
+        } else if (VERSION_14_12.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_12();
                 upgradeFrom14_13();
@@ -1178,8 +1147,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_12, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_13:
+        } else if (VERSION_14_13.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_13();
                 upgradeFrom14_14();
@@ -1194,8 +1162,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_13, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_14:
+        } else if (VERSION_14_14.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_14();
                 upgradeFrom14_15();
@@ -1209,8 +1176,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_14, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_15:
+        } else if (VERSION_14_15.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_15();
                 upgradeFrom14_16();
@@ -1223,8 +1189,7 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_15, e.getLocalizedMessage()));
             }
-            break;
-        case VERSION_14_16:
+        } else if (VERSION_14_16.equals(form.targetVersion)) {
             try {
                 upgradeFrom14_16();
                 upgradeFromAll();
@@ -1236,10 +1201,8 @@ public HtmlResponse upgradeFrom(final UpgradeForm form) {
                 logger.warn("Failed to upgrade data.", e);
                 saveError(messages -> messages.addErrorsFailedToUpgradeFrom(GLOBAL, VERSION_14_16, e.getLocalizedMessage()));
             }
-            break;
-        default:
+        } else {
             saveError(messages -> messages.addErrorsUnknownVersionForUpgrade(GLOBAL));
-            break;
         }
         return redirect(getClass());
     }
diff --git a/src/main/java/org/codelibs/fess/app/web/api/admin/backup/ApiAdminBackupAction.java b/src/main/java/org/codelibs/fess/app/web/api/admin/backup/ApiAdminBackupAction.java
index c21a0adf5..b373f1a0d 100644
--- a/src/main/java/org/codelibs/fess/app/web/api/admin/backup/ApiAdminBackupAction.java
+++ b/src/main/java/org/codelibs/fess/app/web/api/admin/backup/ApiAdminBackupAction.java
@@ -102,17 +102,17 @@ public JsonResponse<ApiResult> files() {
                 });
             }
             final String name = id.substring(0, id.length() - NDJSON_EXTENTION.length());
-            switch (name) {
-            case "search_log":
+            if ("search_log".equals(name)) {
                 return writeNdjsonResponse(id, getSearchLogNdjsonWriteCall());
-            case "user_info":
+            }
+            if ("user_info".equals(name)) {
                 return writeNdjsonResponse(id, getUserInfoNdjsonWriteCall());
-            case "click_log":
+            }
+            if ("click_log".equals(name)) {
                 return writeNdjsonResponse(id, getClickLogNdjsonWriteCall());
-            case "favorite_log":
+            }
+            if ("favorite_log".equals(name)) {
                 return writeNdjsonResponse(id, getFavoriteLogNdjsonWriteCall());
-            default:
-                break;
             }
         }
 
diff --git a/src/main/java/org/codelibs/fess/es/config/exentity/DataConfig.java b/src/main/java/org/codelibs/fess/es/config/exentity/DataConfig.java
index d0a3c26e2..548a61bbe 100644
--- a/src/main/java/org/codelibs/fess/es/config/exentity/DataConfig.java
+++ b/src/main/java/org/codelibs/fess/es/config/exentity/DataConfig.java
@@ -299,30 +299,21 @@ public CrawlerClientFactory initializeClientFactory(final Supplier<CrawlerClient
 
     private AuthScheme getAuthScheme(final Map<String, String> paramMap, final String webAuthName, final String scheme) {
         AuthScheme authScheme = null;
-        switch (scheme) {
-        case Constants.BASIC:
+        if (Constants.BASIC.equals(scheme)) {
             authScheme = new BasicScheme();
-            break;
-        case Constants.DIGEST:
+        } else if (Constants.DIGEST.equals(scheme)) {
             authScheme = new DigestScheme();
-            break;
-        case Constants.NTLM: {
+        } else if (Constants.NTLM.equals(scheme)) {
             final Properties props = new Properties();
             paramMap.entrySet().stream().filter(e -> e.getKey().startsWith("jcifs.")).forEach(e -> {
                 props.setProperty(e.getKey(), e.getValue());
             });
             authScheme = new NTLMScheme(new JcifsEngine(props));
-            break;
-        }
-        case Constants.FORM: {
+        } else if (Constants.FORM.equals(scheme)) {
             final String prefix = CRAWLER_WEB_AUTH + "." + webAuthName + ".";
             final Map<String, String> parameterMap = paramMap.entrySet().stream().filter(e -> e.getKey().startsWith(prefix))
                     .collect(Collectors.toMap(e -> e.getKey().substring(prefix.length()), Entry::getValue));
             authScheme = new FormScheme(parameterMap);
-            break;
-        }
-        default:
-            break;
         }
         return authScheme;
     }
diff --git a/src/main/java/org/codelibs/fess/es/config/exentity/WebAuthentication.java b/src/main/java/org/codelibs/fess/es/config/exentity/WebAuthentication.java
index cd60ad425..242229115 100644
--- a/src/main/java/org/codelibs/fess/es/config/exentity/WebAuthentication.java
+++ b/src/main/java/org/codelibs/fess/es/config/exentity/WebAuthentication.java
@@ -59,12 +59,13 @@ public Authentication getAuthentication() {
 
     private AuthScheme getAuthScheme() {
         final String scheme = getProtocolScheme();
-        switch (scheme) {
-        case Constants.BASIC:
+        if (Constants.BASIC.equals(scheme)) {
             return new BasicScheme();
-        case Constants.DIGEST:
+        }
+        if (Constants.DIGEST.equals(scheme)) {
             return new DigestScheme();
-        case Constants.NTLM: {
+        }
+        if (Constants.NTLM.equals(scheme)) {
             final Properties props = new Properties();
             getWebConfig().getConfigParameterMap(ConfigName.CONFIG).entrySet().stream()
                     .filter(e -> e.getKey().startsWith(Config.JCIFS_PREFIX)).forEach(e -> {
@@ -72,13 +73,10 @@ private AuthScheme getAuthScheme() {
                     });
             return new NTLMScheme(new JcifsEngine(props));
         }
-        case Constants.FORM: {
+        if (Constants.FORM.equals(scheme)) {
             final Map<String, String> parameterMap = ParameterUtil.parse(getParameters());
             return new FormScheme(parameterMap);
         }
-        default:
-            break;
-        }
         return null;
     }
 
diff --git a/src/main/java/org/codelibs/fess/mylasta/direction/FessProp.java b/src/main/java/org/codelibs/fess/mylasta/direction/FessProp.java
index baa4f7514..41d7cc52c 100644
--- a/src/main/java/org/codelibs/fess/mylasta/direction/FessProp.java
+++ b/src/main/java/org/codelibs/fess/mylasta/direction/FessProp.java
@@ -909,15 +909,14 @@ default String[] getSupportedUploadedMediaExtentionsAsArray() {
     String getJobTemplateTitleData();
 
     default String getJobTemplateTitle(final String type) {
-        switch (type) {
-        case Constants.WEB_CRAWLER_TYPE:
+        if (Constants.WEB_CRAWLER_TYPE.equals(type)) {
             return getJobTemplateTitleWeb();
-        case Constants.FILE_CRAWLER_TYPE:
+        }
+        if (Constants.FILE_CRAWLER_TYPE.equals(type)) {
             return getJobTemplateTitleFile();
-        case Constants.DATA_CRAWLER_TYPE:
+        }
+        if (Constants.DATA_CRAWLER_TYPE.equals(type)) {
             return getJobTemplateTitleData();
-        default:
-            break;
         }
         return "None";
     }
diff --git a/src/main/java/org/codelibs/fess/query/TermQueryCommand.java b/src/main/java/org/codelibs/fess/query/TermQueryCommand.java
index 1b8b5d959..8aa63cc1a 100644
--- a/src/main/java/org/codelibs/fess/query/TermQueryCommand.java
+++ b/src/main/java/org/codelibs/fess/query/TermQueryCommand.java
@@ -72,15 +72,14 @@ protected QueryBuilder convertTermQuery(final FessConfig fessConfig, final Query
         if (fessConfig.getQueryReplaceTermWithPrefixQueryAsBoolean() && text.length() > 1 && text.endsWith("*")) {
             return convertPrefixQuery(fessConfig, context, termQuery, boost, field, text);
         }
-        switch (field) {
-        case DEFAULT_FIELD:
+        if (DEFAULT_FIELD.equals(field)) {
             return convertDefaultTermQuery(fessConfig, context, termQuery, boost, field, text);
-        case SORT_FIELD:
+        }
+        if (SORT_FIELD.equals(field)) {
             return convertSortQuery(fessConfig, context, termQuery, boost, field, text);
-        case SITE_FIELD:
+        }
+        if (SITE_FIELD.equals(field)) {
             return convertSiteQuery(fessConfig, context, termQuery, boost, field, text);
-        default:
-            break;
         }
         if (INURL_FIELD.equals(field)
                 || StringUtil.equals(field, context.getDefaultField()) && fessConfig.getIndexFieldUrl().equals(context.getDefaultField())) {
diff --git a/src/main/java/org/codelibs/fess/sso/spnego/SpnegoAuthenticator.java b/src/main/java/org/codelibs/fess/sso/spnego/SpnegoAuthenticator.java
index 97601462b..fbcd8582d 100644
--- a/src/main/java/org/codelibs/fess/sso/spnego/SpnegoAuthenticator.java
+++ b/src/main/java/org/codelibs/fess/sso/spnego/SpnegoAuthenticator.java
@@ -173,8 +173,7 @@ public ServletContext getServletContext() {
 
         @Override
         public String getInitParameter(final String name) {
-            switch (name) {
-            case SpnegoHttpFilter.Constants.LOGGER_LEVEL: {
+            if (SpnegoHttpFilter.Constants.LOGGER_LEVEL.equals(name)) {
                 final String logLevel = getProperty(SPNEGO_LOGGER_LEVEL, StringUtil.EMPTY);
                 if (StringUtil.isNotBlank(logLevel)) {
                     return logLevel;
@@ -193,32 +192,41 @@ public String getInitParameter(final String name) {
                 }
                 return "0";
             }
-            case SpnegoHttpFilter.Constants.LOGIN_CONF:
+            if (SpnegoHttpFilter.Constants.LOGIN_CONF.equals(name)) {
                 return getResourcePath(getProperty(SPNEGO_LOGIN_CONF, "auth_login.conf"));
-            case SpnegoHttpFilter.Constants.KRB5_CONF:
+            }
+            if (SpnegoHttpFilter.Constants.KRB5_CONF.equals(name)) {
                 return getResourcePath(getProperty(SPNEGO_KRB5_CONF, "krb5.conf"));
-            case SpnegoHttpFilter.Constants.CLIENT_MODULE:
+            }
+            if (SpnegoHttpFilter.Constants.CLIENT_MODULE.equals(name)) {
                 return getProperty(SPNEGO_LOGIN_CLIENT_MODULE, "spnego-client");
-            case SpnegoHttpFilter.Constants.SERVER_MODULE:
+            }
+            if (SpnegoHttpFilter.Constants.SERVER_MODULE.equals(name)) {
                 return getProperty(SPNEGO_LOGIN_SERVER_MODULE, "spnego-server");
-            case SpnegoHttpFilter.Constants.PREAUTH_USERNAME:
+            }
+            if (SpnegoHttpFilter.Constants.PREAUTH_USERNAME.equals(name)) {
                 return getProperty(SPNEGO_PREAUTH_USERNAME, "username");
-            case SpnegoHttpFilter.Constants.PREAUTH_PASSWORD:
+            }
+            if (SpnegoHttpFilter.Constants.PREAUTH_PASSWORD.equals(name)) {
                 return getProperty(SPNEGO_PREAUTH_PASSWORD, "password");
-            case SpnegoHttpFilter.Constants.ALLOW_BASIC:
+            }
+            if (SpnegoHttpFilter.Constants.ALLOW_BASIC.equals(name)) {
                 return getProperty(SPNEGO_ALLOW_BASIC, "true");
-            case SpnegoHttpFilter.Constants.ALLOW_UNSEC_BASIC:
+            }
+            if (SpnegoHttpFilter.Constants.ALLOW_UNSEC_BASIC.equals(name)) {
                 return getProperty(SPNEGO_ALLOW_UNSECURE_BASIC, "true");
-            case SpnegoHttpFilter.Constants.PROMPT_NTLM:
+            }
+            if (SpnegoHttpFilter.Constants.PROMPT_NTLM.equals(name)) {
                 return getProperty(SPNEGO_PROMPT_NTLM, "true");
-            case SpnegoHttpFilter.Constants.ALLOW_LOCALHOST:
+            }
+            if (SpnegoHttpFilter.Constants.ALLOW_LOCALHOST.equals(name)) {
                 return getProperty(SPNEGO_ALLOW_LOCALHOST, "true");
-            case SpnegoHttpFilter.Constants.ALLOW_DELEGATION:
+            }
+            if (SpnegoHttpFilter.Constants.ALLOW_DELEGATION.equals(name)) {
                 return getProperty(SPNEGO_ALLOW_DELEGATION, "false");
-            case SpnegoHttpFilter.Constants.EXCLUDE_DIRS:
+            }
+            if (SpnegoHttpFilter.Constants.EXCLUDE_DIRS.equals(name)) {
                 return getProperty(SPNEGO_EXCLUDE_DIRS, StringUtil.EMPTY);
-            default:
-                break;
             }
             return null;
         }