diff --git a/src/main/java/org/codelibs/fess/auth/chain/CommandChain.java b/src/main/java/org/codelibs/fess/auth/chain/CommandChain.java
index 13f92f712..781941789 100644
--- a/src/main/java/org/codelibs/fess/auth/chain/CommandChain.java
+++ b/src/main/java/org/codelibs/fess/auth/chain/CommandChain.java
@@ -27,6 +27,7 @@ import java.util.LinkedList;
 import java.util.List;
 
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.crawler.Constants;
 import org.codelibs.fess.crawler.exception.CrawlerSystemException;
 import org.codelibs.fess.es.user.exentity.User;
@@ -186,11 +187,7 @@ public class CommandChain implements AuthenticationChain {
 
         @Override
         public void run() {
-            try {
-                Thread.sleep(timeout);
-            } catch (final InterruptedException e) {
-                // ignore
-            }
+            ThreadUtil.sleepQuietly(timeout);
 
             if (!finished) {
                 try {
diff --git a/src/main/java/org/codelibs/fess/ds/AbstractDataStore.java b/src/main/java/org/codelibs/fess/ds/AbstractDataStore.java
index 0c950b352..43c9c89cb 100644
--- a/src/main/java/org/codelibs/fess/ds/AbstractDataStore.java
+++ b/src/main/java/org/codelibs/fess/ds/AbstractDataStore.java
@@ -25,6 +25,7 @@ import java.util.Map;
 import java.util.stream.Collectors;
 
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.ds.callback.IndexUpdateCallback;
 import org.codelibs.fess.es.config.exentity.DataConfig;
@@ -137,11 +138,7 @@ public abstract class AbstractDataStore implements DataStore {
     }
 
     protected void sleep(final long interval) {
-        try {
-            Thread.sleep(interval);
-        } catch (final Exception e) {
-            // ignore
-        }
+        ThreadUtil.sleepQuietly(interval);
     }
 
     protected abstract void storeData(DataConfig dataConfig, IndexUpdateCallback callback, Map<String, String> paramMap,
diff --git a/src/main/java/org/codelibs/fess/es/client/FessEsClient.java b/src/main/java/org/codelibs/fess/es/client/FessEsClient.java
index 5a90a6f43..bbedc0385 100644
--- a/src/main/java/org/codelibs/fess/es/client/FessEsClient.java
+++ b/src/main/java/org/codelibs/fess/es/client/FessEsClient.java
@@ -45,6 +45,7 @@ import org.codelibs.core.exception.ResourceNotFoundRuntimeException;
 import org.codelibs.core.io.FileUtil;
 import org.codelibs.core.io.ResourceUtil;
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.curl.CurlResponse;
 import org.codelibs.elasticsearch.client.HttpClient;
 import org.codelibs.elasticsearch.runner.ElasticsearchClusterRunner;
@@ -590,11 +591,7 @@ public class FessEsClient implements Client {
             if (logger.isDebugEnabled()) {
                 logger.debug("Failed to access to Elasticsearch:{}", i, cause);
             }
-            try {
-                Thread.sleep(1000L);
-            } catch (final InterruptedException e) {
-                // ignore
-            }
+            ThreadUtil.sleep(1000L);
         }
         final String message =
                 "Elasticsearch (" + System.getProperty(Constants.FESS_ES_HTTP_ADDRESS)
@@ -625,11 +622,7 @@ public class FessEsClient implements Client {
             if (logger.isDebugEnabled()) {
                 logger.debug("Failed to access to configsync:{}", i, cause);
             }
-            try {
-                Thread.sleep(1000L);
-            } catch (final InterruptedException e) {
-                // ignore
-            }
+            ThreadUtil.sleep(1000L);
         }
         throw cause;
     }
diff --git a/src/main/java/org/codelibs/fess/es/config/exbhv/ScheduledJobBhv.java b/src/main/java/org/codelibs/fess/es/config/exbhv/ScheduledJobBhv.java
index 356097bb1..fbe00ac06 100644
--- a/src/main/java/org/codelibs/fess/es/config/exbhv/ScheduledJobBhv.java
+++ b/src/main/java/org/codelibs/fess/es/config/exbhv/ScheduledJobBhv.java
@@ -18,6 +18,7 @@ package org.codelibs.fess.es.config.exbhv;
 import java.util.regex.Pattern;
 
 import org.apache.commons.lang3.RandomUtils;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.es.config.bsbhv.BsScheduledJobBhv;
 import org.codelibs.fess.es.config.exentity.ScheduledJob;
 import org.codelibs.fess.util.ComponentUtil;
@@ -54,11 +55,7 @@ public class ScheduledJobBhv extends BsScheduledJobBhv {
                     logger.debug("Failed to select a job by {}", id, e);
                 }
                 lastException = e;
-                try {
-                    Thread.sleep(RandomUtils.nextLong(500, 5000));
-                } catch (final InterruptedException e1) {
-                    // ignore
-                }
+                ThreadUtil.sleep(RandomUtils.nextLong(500, 5000));
             }
         }
         logger.warn("Failed to select a job by " + id, lastException);
diff --git a/src/main/java/org/codelibs/fess/exec/Crawler.java b/src/main/java/org/codelibs/fess/exec/Crawler.java
index 0930e16eb..fee42c0f0 100644
--- a/src/main/java/org/codelibs/fess/exec/Crawler.java
+++ b/src/main/java/org/codelibs/fess/exec/Crawler.java
@@ -36,7 +36,9 @@ import java.util.stream.Collectors;
 import javax.annotation.Resource;
 
 import org.codelibs.core.CoreLibConstants;
+import org.codelibs.core.exception.InterruptedRuntimeException;
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.core.misc.DynamicProperties;
 import org.codelibs.core.timer.TimeoutManager;
 import org.codelibs.core.timer.TimeoutTask;
@@ -233,7 +235,7 @@ public class Crawler {
                     while (true) {
                         try {
                             while (!reader.ready()) {
-                                Thread.sleep(1000L);
+                                ThreadUtil.sleep(1000L);
                             }
                             command = reader.readLine().trim();
                             if (logger.isDebugEnabled()) {
@@ -247,7 +249,7 @@ public class Crawler {
                             if (Thread.interrupted()) {
                                 return;
                             }
-                        } catch (final InterruptedException e) {
+                        } catch (final InterruptedRuntimeException e) {
                             return;
                         }
                     }
diff --git a/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java b/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java
index 9c68951cb..4650927e2 100644
--- a/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/DataIndexHelper.java
@@ -22,6 +22,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.app.service.FailureUrlService;
 import org.codelibs.fess.ds.DataStore;
@@ -123,13 +124,7 @@ public class DataIndexHelper {
                 dataCrawlingThreadStatusList.set(startedCrawlerNum, Constants.RUNNING);
                 startedCrawlerNum++;
                 activeCrawlerNum++;
-                try {
-                    Thread.sleep(crawlingExecutionInterval);
-                } catch (final InterruptedException e) {
-                    if (logger.isDebugEnabled()) {
-                        logger.debug("Interrupted.", e);
-                    }
-                }
+                ThreadUtil.sleep(crawlingExecutionInterval);
                 continue;
             }
 
@@ -141,13 +136,7 @@ public class DataIndexHelper {
                     activeCrawlerNum--;
                 }
             }
-            try {
-                Thread.sleep(crawlingExecutionInterval);
-            } catch (final InterruptedException e) {
-                if (logger.isDebugEnabled()) {
-                    logger.debug("Interrupted.", e);
-                }
-            }
+            ThreadUtil.sleep(crawlingExecutionInterval);
         }
 
         boolean finishedAll = false;
diff --git a/src/main/java/org/codelibs/fess/helper/IntervalControlHelper.java b/src/main/java/org/codelibs/fess/helper/IntervalControlHelper.java
index 57a1884a6..453ff96e9 100644
--- a/src/main/java/org/codelibs/fess/helper/IntervalControlHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/IntervalControlHelper.java
@@ -19,6 +19,7 @@ import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.List;
 
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.exception.FessSystemException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -34,26 +35,14 @@ public class IntervalControlHelper {
 
     public void checkCrawlerStatus() {
         while (!crawlerRunning) {
-            try {
-                Thread.sleep(crawlerWaitMillis);
-            } catch (final InterruptedException e) {
-                if (logger.isDebugEnabled()) {
-                    logger.debug("Interrupted.", e);
-                }
-            }
+            ThreadUtil.sleepQuietly(crawlerWaitMillis);
         }
     }
 
     public void delayByRules() {
         final long delay = getDelay();
         if (delay > 0) {
-            try {
-                Thread.sleep(delay);
-            } catch (final InterruptedException e) {
-                if (logger.isDebugEnabled()) {
-                    logger.debug("Interrupted.", e);
-                }
-            }
+            ThreadUtil.sleep(delay);
         }
     }
 
diff --git a/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java b/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java
index d68710545..022664748 100644
--- a/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/KeyMatchHelper.java
@@ -25,6 +25,7 @@ import javax.annotation.PostConstruct;
 
 import org.codelibs.core.concurrent.CommonPoolUtil;
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.core.misc.Pair;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.entity.SearchRequestParams.SearchRequestType;
@@ -108,13 +109,7 @@ public class KeyMatchHelper {
                     }
 
                     if (interval > 0) {
-                        try {
-                            Thread.sleep(interval);
-                        } catch (final InterruptedException e) {
-                            if (logger.isDebugEnabled()) {
-                                logger.debug("Interrupted.", e);
-                            }
-                        }
+                        ThreadUtil.sleep(interval);
                     }
                 });
         this.keyMatchQueryMap = keyMatchQueryMap;
diff --git a/src/main/java/org/codelibs/fess/helper/SystemHelper.java b/src/main/java/org/codelibs/fess/helper/SystemHelper.java
index 9ea97c85e..055d5b141 100644
--- a/src/main/java/org/codelibs/fess/helper/SystemHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/SystemHelper.java
@@ -52,6 +52,7 @@ import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.core.config.Configurator;
 import org.codelibs.core.exception.IORuntimeException;
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.core.misc.Pair;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.crawler.util.CharUtil;
@@ -369,14 +370,9 @@ public class SystemHelper {
         }
     }
 
+    @Deprecated
     public void sleep(final int sec) {
-        try {
-            Thread.sleep(sec * 1000L);
-        } catch (final InterruptedException e) {
-            if (logger.isDebugEnabled()) {
-                logger.debug("Interrupted.", e);
-            }
-        }
+        ThreadUtil.sleepQuietly(sec * 1000L);
     }
 
     public void addShutdownHook(final Runnable hook) {
diff --git a/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java b/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java
index ad895281e..4bad09412 100644
--- a/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java
+++ b/src/main/java/org/codelibs/fess/helper/WebFsIndexHelper.java
@@ -25,6 +25,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.regex.Pattern;
 
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.crawler.Crawler;
 import org.codelibs.fess.crawler.CrawlerContext;
@@ -365,13 +366,7 @@ public class WebFsIndexHelper {
                 crawlerStatusList.set(startedCrawlerNum, Constants.RUNNING);
                 startedCrawlerNum++;
                 activeCrawlerNum++;
-                try {
-                    Thread.sleep(crawlingExecutionInterval);
-                } catch (final InterruptedException e) {
-                    if (logger.isDebugEnabled()) {
-                        logger.debug("Interrupted.", e);
-                    }
-                }
+                ThreadUtil.sleep(crawlingExecutionInterval);
                 continue;
             }
 
@@ -386,13 +381,7 @@ public class WebFsIndexHelper {
                     activeCrawlerNum--;
                 }
             }
-            try {
-                Thread.sleep(crawlingExecutionInterval);
-            } catch (final InterruptedException e) {
-                if (logger.isDebugEnabled()) {
-                    logger.debug("Interrupted.", e);
-                }
-            }
+            ThreadUtil.sleep(crawlingExecutionInterval);
         }
 
         boolean finishedAll = false;
diff --git a/src/main/java/org/codelibs/fess/indexer/IndexUpdater.java b/src/main/java/org/codelibs/fess/indexer/IndexUpdater.java
index 7c7adfb6e..b913d360e 100644
--- a/src/main/java/org/codelibs/fess/indexer/IndexUpdater.java
+++ b/src/main/java/org/codelibs/fess/indexer/IndexUpdater.java
@@ -24,6 +24,7 @@ import javax.annotation.PreDestroy;
 import javax.annotation.Resource;
 
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.crawler.Crawler;
 import org.codelibs.fess.crawler.entity.AccessResult;
@@ -190,11 +191,7 @@ public class IndexUpdater extends Thread {
                     final long interval = updateInterval - updateTime;
                     if (interval > 0) {
                         // sleep
-                        try {
-                            Thread.sleep(interval); // 10 sec (default)
-                        } catch (final InterruptedException e) {
-                            logger.warn("Interrupted index update.", e);
-                        }
+                        ThreadUtil.sleep(interval); // 10 sec (default)
                     }
 
                     docList.clear();
@@ -217,11 +214,7 @@ public class IndexUpdater extends Thread {
                     long hitCount = ((EsResultList<EsAccessResult>) arList).getTotalHits();
                     while (hitCount > 0) {
                         if (arList.isEmpty()) {
-                            try {
-                                Thread.sleep(fessConfig.getIndexerWebfsCommitMarginTimeAsInteger().longValue());
-                            } catch (final Exception e) {
-                                // ignore
-                            }
+                            ThreadUtil.sleep(fessConfig.getIndexerWebfsCommitMarginTimeAsInteger().longValue());
                             cleanupTime = -1;
                         } else {
                             processAccessResults(docList, accessResultList, arList);
diff --git a/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java b/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java
index a7a9f1063..8e481de71 100644
--- a/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java
+++ b/src/main/java/org/codelibs/fess/thumbnail/ThumbnailManager.java
@@ -37,6 +37,7 @@ import javax.annotation.PostConstruct;
 import javax.annotation.PreDestroy;
 
 import org.codelibs.core.lang.StringUtil;
+import org.codelibs.core.lang.ThreadUtil;
 import org.codelibs.core.misc.Tuple3;
 import org.codelibs.fess.Constants;
 import org.codelibs.fess.es.client.FessEsClient;
@@ -252,7 +253,7 @@ public class ThumbnailManager {
                     } else {
                         final long interval = fessConfig.getThumbnailGeneratorIntervalAsInteger().longValue();
                         if (interval > 0) {
-                            Thread.sleep(interval);
+                            ThreadUtil.sleep(interval);
                         }
                     }
                 } else {