diff --git a/src/main/scala/app/IndexController.scala b/src/main/scala/app/IndexController.scala
index 6cc95b6..802b9b1 100644
--- a/src/main/scala/app/IndexController.scala
+++ b/src/main/scala/app/IndexController.scala
@@ -59,7 +59,7 @@
     updateLastLoginDate(account.userName)
 
     flash.get(Keys.Flash.Redirect).asInstanceOf[Option[String]].map { redirectUrl =>
-      if(redirectUrl.replaceFirst("/$", "") == request.getContextPath){
+      if(redirectUrl.stripSuffix("/") == request.getContextPath){
         redirect("/")
       } else {
         redirect(redirectUrl)
diff --git a/src/main/scala/app/LabelsController.scala b/src/main/scala/app/LabelsController.scala
index 2a222bd..acbfef8 100644
--- a/src/main/scala/app/LabelsController.scala
+++ b/src/main/scala/app/LabelsController.scala
@@ -53,7 +53,7 @@
    */
   private def labelName: Constraint = new Constraint(){
     override def validate(name: String, value: String, messages: Messages): Option[String] =
-      if(!value.matches("^[^,]+$")){
+      if(value.contains(',')){
         Some(s"${name} contains invalid character.")
       } else if(value.startsWith("_") || value.startsWith("-")){
         Some(s"${name} starts with invalid character.")
@@ -62,4 +62,4 @@
       }
   }
 
-}
\ No newline at end of file
+}
diff --git a/src/main/scala/app/RepositoryViewerController.scala b/src/main/scala/app/RepositoryViewerController.scala
index 6798c0a..63ba043 100644
--- a/src/main/scala/app/RepositoryViewerController.scala
+++ b/src/main/scala/app/RepositoryViewerController.scala
@@ -255,7 +255,7 @@
     val name = multiParams("splat").head
 
     if(name.endsWith(".zip")){
-      val revision = name.replaceFirst("\\.zip$", "")
+      val revision = name.stripSuffix(".zip")
       val workDir = getDownloadWorkDir(repository.owner, repository.name, session.getId)
       if(workDir.exists){
         FileUtils.deleteDirectory(workDir)
@@ -316,9 +316,9 @@
       case branch if(path == branch || path.startsWith(branch + "/")) => branch
     } orElse repository.tags.collectFirst {
       case tag if(path == tag.name || path.startsWith(tag.name + "/")) => tag.name
-    } orElse Some(path.split("/")(0)) get
+    } getOrElse path.split("/")(0)
 
-    (id, path.substring(id.length).replaceFirst("^/", ""))
+    (id, path.substring(id.length).stripPrefix("/"))
   }
 
 
diff --git a/src/main/scala/service/AccountService.scala b/src/main/scala/service/AccountService.scala
index acd76c9..d349fc7 100644
--- a/src/main/scala/service/AccountService.scala
+++ b/src/main/scala/service/AccountService.scala
@@ -44,7 +44,7 @@
             getAccountByUserName(ldapUserInfo.userName)
           }
           case Some(x) if(x.isRemoved)  => {
-            logger.info(s"LDAP Authentication Failed: Account is already registered but disabled..")
+            logger.info("LDAP Authentication Failed: Account is already registered but disabled.")
             defaultAuthentication(userName, password)
           }
           case None => getAccountByMailAddress(ldapUserInfo.mailAddress, true) match {
@@ -53,7 +53,7 @@
               getAccountByUserName(ldapUserInfo.userName)
             }
             case Some(x) if(x.isRemoved)  => {
-              logger.info(s"LDAP Authentication Failed: Account is already registered but disabled..")
+              logger.info("LDAP Authentication Failed: Account is already registered but disabled.")
               defaultAuthentication(userName, password)
             }
             case None => {
@@ -165,4 +165,4 @@
 
 }
 
-object AccountService extends AccountService
\ No newline at end of file
+object AccountService extends AccountService
diff --git a/src/main/scala/service/RepositorySearchService.scala b/src/main/scala/service/RepositorySearchService.scala
index 33ec942..3868ad9 100644
--- a/src/main/scala/service/RepositorySearchService.scala
+++ b/src/main/scala/service/RepositorySearchService.scala
@@ -6,7 +6,6 @@
 import model.Issue
 import org.eclipse.jgit.revwalk.RevWalk
 import org.eclipse.jgit.treewalk.TreeWalk
-import scala.collection.mutable.ListBuffer
 import org.eclipse.jgit.lib.FileMode
 import org.eclipse.jgit.api.Git
 
@@ -39,7 +38,7 @@
         Nil
       } else {
         val files = searchRepositoryFiles(git, query)
-        val commits = JGitUtil.getLatestCommitFromPaths(git, files.toList.map(_._1), "HEAD")
+        val commits = JGitUtil.getLatestCommitFromPaths(git, files.map(_._1), "HEAD")
         files.map { case (path, text) =>
           val (highlightText, lineNumber)  = getHighlightText(text, query)
           FileSearchResult(
@@ -60,7 +59,7 @@
     treeWalk.addTree(revCommit.getTree)
 
     val keywords = StringUtil.splitWords(query.toLowerCase)
-    val list = new ListBuffer[(String, String)]
+    val list = new scala.collection.mutable.ListBuffer[(String, String)]
 
     while (treeWalk.next()) {
       val mode = treeWalk.getFileMode(0)
diff --git a/src/main/scala/service/SystemSettingsService.scala b/src/main/scala/service/SystemSettingsService.scala
index fd72b60..917747a 100644
--- a/src/main/scala/service/SystemSettingsService.scala
+++ b/src/main/scala/service/SystemSettingsService.scala
@@ -111,7 +111,7 @@
       defining(request.getRequestURL.toString){ url =>
         url.substring(0, url.length - (request.getRequestURI.length - request.getContextPath.length))
       }
-    }.replaceFirst("/$", "")
+    }.stripSuffix("/")
   }
 
   case class Ldap(
diff --git a/src/main/scala/service/WebHookService.scala b/src/main/scala/service/WebHookService.scala
index 5662c44..795123b 100644
--- a/src/main/scala/service/WebHookService.scala
+++ b/src/main/scala/service/WebHookService.scala
@@ -87,7 +87,7 @@
         refName,
         commits.map { commit =>
           val diffs = JGitUtil.getDiffs(git, commit.id, false)
-          val commitUrl = repositoryInfo.httpUrl.replaceFirst("/git/", "/").replaceFirst("\\.git$", "") + "/commit/" + commit.id
+          val commitUrl = repositoryInfo.httpUrl.replaceFirst("/git/", "/").stripSuffix(".git") + "/commit/" + commit.id
 
           WebHookCommit(
             id        = commit.id,
@@ -103,7 +103,7 @@
               email = commit.mailAddress
             )
           )
-        }.toList,
+        },
         WebHookRepository(
           name        = repositoryInfo.name,
           url         = repositoryInfo.httpUrl,
diff --git a/src/main/scala/service/WikiService.scala b/src/main/scala/service/WikiService.scala
index 20fa764..7f5f908 100644
--- a/src/main/scala/service/WikiService.scala
+++ b/src/main/scala/service/WikiService.scala
@@ -97,7 +97,7 @@
     using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
       JGitUtil.getFileList(git, "master", ".")
         .filter(_.name.endsWith(".md"))
-        .map(_.name.replaceFirst("\\.md$", ""))
+        .map(_.name.stripSuffix(".md"))
         .sortBy(x => x)
     }
   }
@@ -143,7 +143,7 @@
           val revertInfo = (p.getFiles.asScala.map { fh =>
             fh.getChangeType match {
               case DiffEntry.ChangeType.MODIFY => {
-                val source = getWikiPage(owner, repository, fh.getNewPath.replaceFirst("\\.md$", "")).map(_.content).getOrElse("")
+                val source = getWikiPage(owner, repository, fh.getNewPath.stripSuffix(".md")).map(_.content).getOrElse("")
                 val applied = PatchUtil.apply(source, patch, fh)
                 if(applied != null){
                   Seq(RevertInfo("ADD", fh.getNewPath, applied))
diff --git a/src/main/scala/servlet/GitRepositoryServlet.scala b/src/main/scala/servlet/GitRepositoryServlet.scala
index 0e43432..4da9cd3 100644
--- a/src/main/scala/servlet/GitRepositoryServlet.scala
+++ b/src/main/scala/servlet/GitRepositoryServlet.scala
@@ -76,7 +76,7 @@
 
     defining(request.paths){ paths =>
       val owner      = paths(1)
-      val repository = paths(2).replaceFirst("\\.git$", "")
+      val repository = paths(2).stripSuffix(".git")
 
       logger.debug("repository:" + owner + "/" + repository)
 
diff --git a/src/main/scala/ssh/SshUtil.scala b/src/main/scala/ssh/SshUtil.scala
index 50e1cc9..9d6484c 100644
--- a/src/main/scala/ssh/SshUtil.scala
+++ b/src/main/scala/ssh/SshUtil.scala
@@ -14,7 +14,7 @@
     // TODO RFC 4716 Public Key is not supported...
     val parts = key.split(" ")
     if (parts.size < 2) {
-      logger.debug(s"Invalid PublicKey Format: key")
+      logger.debug(s"Invalid PublicKey Format: ${key}")
       return None
     }
     try {
diff --git a/src/main/scala/util/JGitUtil.scala b/src/main/scala/util/JGitUtil.scala
index 282469e..48c4ad7 100644
--- a/src/main/scala/util/JGitUtil.scala
+++ b/src/main/scala/util/JGitUtil.scala
@@ -146,12 +146,12 @@
           commitCount,
           // branches
           git.branchList.call.asScala.map { ref =>
-            ref.getName.replaceFirst("^refs/heads/", "")
+            ref.getName.stripPrefix("refs/heads/")
           }.toList,
           // tags
           git.tagList.call.asScala.map { ref =>
             val revCommit = getRevCommitFromId(git, ref.getObjectId)
-            TagInfo(ref.getName.replaceFirst("^refs/tags/", ""), revCommit.getCommitterIdent.getWhen, revCommit.getName)
+            TagInfo(ref.getName.stripPrefix("refs/tags/"), revCommit.getCommitterIdent.getWhen, revCommit.getName)
           }.toList
         )
       } catch {
@@ -190,7 +190,7 @@
               val targetPath = walker.getPathString
               if((path + "/").startsWith(targetPath)){
                 true
-              } else if(targetPath.startsWith(path + "/") && targetPath.substring(path.length + 1).indexOf("/") < 0){
+              } else if(targetPath.startsWith(path + "/") && targetPath.substring(path.length + 1).indexOf('/') < 0){
                 stopRecursive = true
                 treeWalk.setRecursive(false)
                 true
diff --git a/src/main/scala/util/Validations.scala b/src/main/scala/util/Validations.scala
index ebb0072..ce4c182 100644
--- a/src/main/scala/util/Validations.scala
+++ b/src/main/scala/util/Validations.scala
@@ -10,7 +10,7 @@
    */
   def identifier: Constraint = new Constraint(){
     override def validate(name: String, value: String, messages: Messages): Option[String] =
-      if(!value.matches("^[a-zA-Z0-9\\-_.]+$")){
+      if(!value.matches("[a-zA-Z0-9\\-_.]+")){
         Some(s"${name} contains invalid character.")
       } else if(value.startsWith("_") || value.startsWith("-")){
         Some(s"${name} starts with invalid character.")
diff --git a/src/main/scala/view/Markdown.scala b/src/main/scala/view/Markdown.scala
index a66f9f7..8a50865 100644
--- a/src/main/scala/view/Markdown.scala
+++ b/src/main/scala/view/Markdown.scala
@@ -45,7 +45,7 @@
           (text, text)
         }
 
-        val url = repository.httpUrl.replaceFirst("/git/", "/").replaceFirst("\\.git$", "") + "/wiki/" + StringUtil.urlEncode(page)
+        val url = repository.httpUrl.replaceFirst("/git/", "/").stripSuffix(".git") + "/wiki/" + StringUtil.urlEncode(page)
 
         if(getWikiPage(repository.owner, repository.name, page).isDefined){
           new Rendering(url, label)
@@ -105,7 +105,7 @@
     if(!enableWikiLink || url.startsWith("http://") || url.startsWith("https://") || url.startsWith("#")){
       url
     } else {
-      repository.httpUrl.replaceFirst("/git/", "/").replaceFirst("\\.git$", "") + "/wiki/_blob/" + url
+      repository.httpUrl.replaceFirst("/git/", "/").stripSuffix(".git") + "/wiki/_blob/" + url
     }
   }
 
diff --git a/src/main/scala/view/helpers.scala b/src/main/scala/view/helpers.scala
index a20a6b3..ddf4a0a 100644
--- a/src/main/scala/view/helpers.scala
+++ b/src/main/scala/view/helpers.scala
@@ -196,7 +196,6 @@
       case x if(x.endsWith(".sql"))     => "sql"
       case x if(x.endsWith(".tcl"))     => "tcl"
       case x if(x.endsWith(".vbs"))     => "vbscript"
-      case x if(x.endsWith(".tcl"))     => "tcl"
       case x if(x.endsWith(".yml"))     => "yaml"
       case _ => "plain_text"
     }