diff --git a/src/main/java/org/codelibs/fess/api/BaseJsonApiManager.java b/src/main/java/org/codelibs/fess/api/BaseJsonApiManager.java
index 0d82fe66d0b45db23a73e56866ddb6b7ba0097d8..7a0fbe28ad18389096edd8c0f312914c215e58f0 100644
--- a/src/main/java/org/codelibs/fess/api/BaseJsonApiManager.java
+++ b/src/main/java/org/codelibs/fess/api/BaseJsonApiManager.java
@@ -79,7 +79,7 @@ public abstract class BaseJsonApiManager extends BaseApiManager {
     }
 
     protected void writeJsonResponse(final int status, final String body) {
-        final String callback = LaRequestUtil.getOptionalRequest().map(req -> req.getParameter("callback")).get();
+        final String callback = LaRequestUtil.getOptionalRequest().map(req -> req.getParameter("callback")).orElse(null);
         final boolean isJsonp = ComponentUtil.getFessConfig().isApiJsonpEnabled() && StringUtil.isNotBlank(callback);
 
         final StringBuilder buf = new StringBuilder(1000);
diff --git a/src/main/java/org/codelibs/fess/app/web/admin/searchlist/ListForm.java b/src/main/java/org/codelibs/fess/app/web/admin/searchlist/ListForm.java
index 3bb780dd380d5995bdb16a473e723342231fb2df..75d0578f9abeaae0605907383c4dcff511105c1a 100644
--- a/src/main/java/org/codelibs/fess/app/web/admin/searchlist/ListForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/admin/searchlist/ListForm.java
@@ -142,7 +142,7 @@ public class ListForm extends SearchRequestParams {
 
     @Override
     public Object getAttribute(final String name) {
-        return LaRequestUtil.getOptionalRequest().map(req -> req.getAttribute(name)).get();
+        return LaRequestUtil.getOptionalRequest().map(req -> req.getAttribute(name)).orElse(null);
     }
 
     @Override
diff --git a/src/main/java/org/codelibs/fess/app/web/base/SearchForm.java b/src/main/java/org/codelibs/fess/app/web/base/SearchForm.java
index 8f63fd675472d5d542aed61fac16db0e29585df9..69c62259dfbeb99687e1f1c6da60ca1050f3fbf2 100644
--- a/src/main/java/org/codelibs/fess/app/web/base/SearchForm.java
+++ b/src/main/java/org/codelibs/fess/app/web/base/SearchForm.java
@@ -135,7 +135,7 @@ public class SearchForm extends SearchRequestParams {
 
     @Override
     public Object getAttribute(final String name) {
-        return LaRequestUtil.getOptionalRequest().map(req -> req.getAttribute(name)).get();
+        return LaRequestUtil.getOptionalRequest().map(req -> req.getAttribute(name)).orElse(null);
     }
 
     @Override
diff --git a/src/main/java/org/codelibs/fess/helper/UserInfoHelper.java b/src/main/java/org/codelibs/fess/helper/UserInfoHelper.java
index b355c9474ae67c6ba151360351c125b41374095d..fd0cb7b71ba2851b5aa96c4a3e0ef3e75922ff1a 100644
--- a/src/main/java/org/codelibs/fess/helper/UserInfoHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/UserInfoHelper.java
@@ -80,7 +80,7 @@ public class UserInfoHelper {
                 updateUserSessionId(userCode);
             }
             return userCode;
-        }).get();
+        }).orElse(null);
     }
 
     protected String getUserCodeFromUserBean(final HttpServletRequest request) {
diff --git a/src/main/java/org/codelibs/fess/taglib/FessFunctions.java b/src/main/java/org/codelibs/fess/taglib/FessFunctions.java
index eb609eff0e4bdecf441e0f962d7f57b94dd68677..180d80030bfafcc04286a79a39af321c64edc78c 100644
--- a/src/main/java/org/codelibs/fess/taglib/FessFunctions.java
+++ b/src/main/java/org/codelibs/fess/taglib/FessFunctions.java
@@ -286,7 +286,7 @@ public class FessFunctions {
                 request.setAttribute(key, query);
             }
             return query;
-        }).get();
+        }).orElse(null);
     }
 
     private static String createForm(final String key, final String prefix) {
@@ -314,7 +314,7 @@ public class FessFunctions {
                 request.setAttribute(key, query);
             }
             return query;
-        }).get();
+        }).orElse(null);
     }
 
     public static String base64(final String value) {
diff --git a/src/main/java/org/codelibs/fess/util/WebApiUtil.java b/src/main/java/org/codelibs/fess/util/WebApiUtil.java
index 484c25986dfbf185f5e2091b47513eeab784e427..9fd5d05f965789f58c17c6c18f96926227403df9 100644
--- a/src/main/java/org/codelibs/fess/util/WebApiUtil.java
+++ b/src/main/java/org/codelibs/fess/util/WebApiUtil.java
@@ -31,7 +31,7 @@ public final class WebApiUtil {
 
     @SuppressWarnings("unchecked")
     public static <T> T getObject(final String name) {
-        return LaRequestUtil.getOptionalRequest().map(req -> (T) req.getAttribute(name)).get();
+        return LaRequestUtil.getOptionalRequest().map(req -> (T) req.getAttribute(name)).orElse(null);
     }
 
     public static void setError(final int statusCode, final String message) {