diff --git a/src/main/scala/app/CreateRepositoryController.scala b/src/main/scala/app/CreateRepositoryController.scala
index 0a9ebe7..560b828 100644
--- a/src/main/scala/app/CreateRepositoryController.scala
+++ b/src/main/scala/app/CreateRepositoryController.scala
@@ -1,6 +1,7 @@
 package app
 
 import util.Directory._
+import util.ControlUtil._
 import util._
 import service._
 import java.io.File
@@ -149,7 +150,7 @@
           getWikiRepositoryDir(loginUserName, repository.name))
 
         // insert commit id
-        JGitUtil.withGit(getRepositoryDir(loginUserName, repository.name)){ git =>
+        using(Git.open(getRepositoryDir(loginUserName, repository.name))){ git =>
           JGitUtil.getRepositoryInfo(loginUserName, repository.name, baseUrl).branchList.foreach { branch =>
             JGitUtil.getCommitLog(git, branch) match {
               case Right((commits, _)) => commits.foreach { commit =>
diff --git a/src/main/scala/app/PullRequestsController.scala b/src/main/scala/app/PullRequestsController.scala
index e7035d6..46bae76 100644
--- a/src/main/scala/app/PullRequestsController.scala
+++ b/src/main/scala/app/PullRequestsController.scala
@@ -3,6 +3,7 @@
 import util.{LockUtil, CollaboratorsAuthenticator, JGitUtil, ReferrerAuthenticator, Notifier}
 import util.Directory._
 import util.Implicits._
+import util.ControlUtil._
 import service._
 import org.eclipse.jgit.api.Git
 import jp.sf.amateras.scalatra.forms._
@@ -67,7 +68,7 @@
     val issueId = params("id").toInt
 
     getPullRequest(owner, name, issueId) map { case(issue, pullreq) =>
-      JGitUtil.withGit(getRepositoryDir(owner, name)){ git =>
+      using(Git.open(getRepositoryDir(owner, name))){ git =>
         val requestCommitId = git.getRepository.resolve(pullreq.requestBranch)
 
         val (commits, diffs) =
@@ -219,7 +220,7 @@
         } getOrElse NotFound
       }
       case _ => {
-        JGitUtil.withGit(getRepositoryDir(forkedRepository.owner, forkedRepository.name)){ git =>
+        using(Git.open(getRepositoryDir(forkedRepository.owner, forkedRepository.name))){ git =>
           val defaultBranch = JGitUtil.getDefaultBranch(git, forkedRepository).get._2
           redirect(s"${context.path}/${forkedRepository.owner}/${forkedRepository.name}/compare/${defaultBranch}...${defaultBranch}")
         }
@@ -299,7 +300,7 @@
       commitIdTo            = form.commitIdTo)
 
     // fetch requested branch
-    JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
       git.fetch
         .setRemote(getRepositoryDir(form.requestUserName, repository.name).toURI.toString)
         .setRefSpecs(new RefSpec(s"refs/heads/${form.requestBranch}:refs/pull/${issueId}/head"))
diff --git a/src/main/scala/app/RepositorySettingsController.scala b/src/main/scala/app/RepositorySettingsController.scala
index 5640e8e..bc4cf86 100644
--- a/src/main/scala/app/RepositorySettingsController.scala
+++ b/src/main/scala/app/RepositorySettingsController.scala
@@ -2,15 +2,14 @@
 
 import service._
 import util.Directory._
-import util.{JGitUtil, UsersAuthenticator, OwnerAuthenticator}
+import util.{UsersAuthenticator, OwnerAuthenticator}
 import jp.sf.amateras.scalatra.forms._
 import org.apache.commons.io.FileUtils
 import org.scalatra.FlashMapSupport
-import service.WebHookService.{WebHookRepository, WebHookUser, WebHookCommit, WebHookPayload}
-import org.eclipse.jgit.diff.DiffEntry
-import scala.collection.mutable.ListBuffer
-import org.eclipse.jgit.revwalk.RevCommit
+import service.WebHookService.WebHookPayload
 import util.JGitUtil.CommitInfo
+import util.ControlUtil._
+import org.eclipse.jgit.api.Git
 
 class RepositorySettingsController extends RepositorySettingsControllerBase
   with RepositoryService with AccountService with WebHookService
@@ -132,7 +131,7 @@
    * Send the test request to registered web hook URLs.
    */
   get("/:owner/:repository/settings/hooks/test")(ownerOnly { repository =>
-    JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
       import scala.collection.JavaConverters._
       val commits = git.log
         .add(git.getRepository.resolve(repository.repository.defaultBranch))
diff --git a/src/main/scala/app/RepositoryViewerController.scala b/src/main/scala/app/RepositoryViewerController.scala
index df7fd8a..adb9d04 100644
--- a/src/main/scala/app/RepositoryViewerController.scala
+++ b/src/main/scala/app/RepositoryViewerController.scala
@@ -2,6 +2,7 @@
 
 import util.Directory._
 import util.Implicits._
+import util.ControlUtil._
 import _root_.util.{ReferrerAuthenticator, JGitUtil, FileUtil, StringUtil}
 import service._
 import org.scalatra._
@@ -56,7 +57,7 @@
     val (branchName, path) = splitPath(repository, multiParams("splat").head)
     val page = params.getOrElse("page", "1").toInt
 
-    JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
       JGitUtil.getCommitLog(git, branchName, page, 30, path) match {
         case Right((logs, hasNext)) =>
           repo.html.commits(if(path.isEmpty) Nil else path.split("/").toList, branchName, repository,
@@ -75,7 +76,7 @@
     val (id, path) = splitPath(repository, multiParams("splat").head)
     val raw = params.get("raw").getOrElse("false").toBoolean
 
-    JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
       val revCommit = JGitUtil.getRevCommitFromId(git, git.getRepository.resolve(id))
 
       @scala.annotation.tailrec
@@ -127,7 +128,7 @@
   get("/:owner/:repository/commit/:id")(referrersOnly { repository =>
     val id = params("id")
 
-    JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
       val revCommit = JGitUtil.getRevCommitFromId(git, git.getRepository.resolve(id))
 
       JGitUtil.getDiffs(git, id) match { case (diffs, oldCommitId) =>
@@ -143,7 +144,7 @@
    * Displays branches.
    */
   get("/:owner/:repository/branches")(referrersOnly { repository =>
-    JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
       // retrieve latest update date of each branch
       val branchInfo = repository.branchList.map { branchName =>
         val revCommit = git.log.add(git.getRepository.resolve(branchName)).setMaxCount(1).call.iterator.next
@@ -176,7 +177,7 @@
       
       // clone the repository
       val cloneDir = new File(workDir, revision)
-      JGitUtil.withGit(Git.cloneRepository
+      using(Git.cloneRepository
           .setURI(getRepositoryDir(repository.owner, repository.name).toURI.toString)
           .setDirectory(cloneDir)
           .call){ git =>
@@ -233,10 +234,10 @@
     if(repository.commitCount == 0){
       repo.html.guide(repository)
     } else {
-      JGitUtil.withGit(getRepositoryDir(repository.owner, repository.name)){ git =>
+      using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
         val revisions = Seq(if(revstr.isEmpty) repository.repository.defaultBranch else revstr, repository.branchList.head)
         // get specified commit
-      JGitUtil.getDefaultBranch(git, repository, revstr).map { case (objectId, revision) =>
+        JGitUtil.getDefaultBranch(git, repository, revstr).map { case (objectId, revision) =>
           val revCommit = JGitUtil.getRevCommitFromId(git, objectId)
 
           // get files
diff --git a/src/main/scala/app/WikiController.scala b/src/main/scala/app/WikiController.scala
index 8a27bb2..a44f9af 100644
--- a/src/main/scala/app/WikiController.scala
+++ b/src/main/scala/app/WikiController.scala
@@ -3,7 +3,9 @@
 import service._
 import util.{CollaboratorsAuthenticator, ReferrerAuthenticator, JGitUtil, StringUtil}
 import util.Directory._
+import util.ControlUtil._
 import jp.sf.amateras.scalatra.forms._
+import org.eclipse.jgit.api.Git
 
 class WikiController extends WikiControllerBase 
   with WikiService with RepositoryService with AccountService with ActivityService
@@ -46,7 +48,7 @@
   get("/:owner/:repository/wiki/:page/_history")(referrersOnly { repository =>
     val pageName = StringUtil.urlDecode(params("page"))
 
-    JGitUtil.withGit(getWikiRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getWikiRepositoryDir(repository.owner, repository.name))){ git =>
       JGitUtil.getCommitLog(git, "master", path = pageName + ".md") match {
         case Right((logs, hasNext)) => wiki.html.history(Some(pageName), logs, repository)
         case Left(_) => NotFound
@@ -58,7 +60,7 @@
     val pageName = StringUtil.urlDecode(params("page"))
     val commitId = params("commitId").split("\\.\\.\\.")
 
-    JGitUtil.withGit(getWikiRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getWikiRepositoryDir(repository.owner, repository.name))){ git =>
       wiki.html.compare(Some(pageName), JGitUtil.getDiffs(git, commitId(0), commitId(1), true), repository)
     }
   })
@@ -66,7 +68,7 @@
   get("/:owner/:repository/wiki/_compare/:commitId")(referrersOnly { repository =>
     val commitId   = params("commitId").split("\\.\\.\\.")
 
-    JGitUtil.withGit(getWikiRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getWikiRepositoryDir(repository.owner, repository.name))){ git =>
       wiki.html.compare(None, JGitUtil.getDiffs(git, commitId(0), commitId(1), true), repository)
     }
   })
@@ -120,7 +122,7 @@
   })
   
   get("/:owner/:repository/wiki/_history")(referrersOnly { repository =>
-    JGitUtil.withGit(getWikiRepositoryDir(repository.owner, repository.name)){ git =>
+    using(Git.open(getWikiRepositoryDir(repository.owner, repository.name))){ git =>
       JGitUtil.getCommitLog(git, "master") match {
         case Right((logs, hasNext)) => wiki.html.history(None, logs, repository)
         case Left(_) => NotFound
diff --git a/src/main/scala/service/RepositorySearchService.scala b/src/main/scala/service/RepositorySearchService.scala
index 4c80441..1baed45 100644
--- a/src/main/scala/service/RepositorySearchService.scala
+++ b/src/main/scala/service/RepositorySearchService.scala
@@ -2,6 +2,7 @@
 
 import util.{FileUtil, StringUtil, JGitUtil}
 import util.Directory._
+import util.ControlUtil._
 import model.Issue
 import org.eclipse.jgit.revwalk.RevWalk
 import org.eclipse.jgit.treewalk.TreeWalk
@@ -27,12 +28,12 @@
     }
 
   def countFiles(owner: String, repository: String, query: String): Int =
-    JGitUtil.withGit(getRepositoryDir(owner, repository)){ git =>
+    using(Git.open(getRepositoryDir(owner, repository))){ git =>
       if(JGitUtil.isEmpty(git)) 0 else searchRepositoryFiles(git, query).length
     }
 
   def searchFiles(owner: String, repository: String, query: String): List[FileSearchResult] =
-    JGitUtil.withGit(getRepositoryDir(owner, repository)){ git =>
+    using(Git.open(getRepositoryDir(owner, repository))){ git =>
       if(JGitUtil.isEmpty(git)){
         Nil
       } else {
diff --git a/src/main/scala/service/WikiService.scala b/src/main/scala/service/WikiService.scala
index ae5e300..2a1a945 100644
--- a/src/main/scala/service/WikiService.scala
+++ b/src/main/scala/service/WikiService.scala
@@ -5,6 +5,7 @@
 import org.eclipse.jgit.api.Git
 import org.apache.commons.io.FileUtils
 import util.{Directory, JGitUtil, LockUtil}
+import util.ControlUtil._
 
 object WikiService {
   
@@ -52,7 +53,7 @@
    * Returns the wiki page.
    */
   def getWikiPage(owner: String, repository: String, pageName: String): Option[WikiPageInfo] = {
-    JGitUtil.withGit(Directory.getWikiRepositoryDir(owner, repository)){ git =>
+    using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
       if(!JGitUtil.isEmpty(git)){
         JGitUtil.getFileList(git, "master", ".").find(_.name == pageName + ".md").map { file =>
           WikiPageInfo(file.name, new String(git.getRepository.open(file.id).getBytes, "UTF-8"), file.committer, file.time)
@@ -65,7 +66,7 @@
    * Returns the content of the specified file.
    */
   def getFileContent(owner: String, repository: String, path: String): Option[Array[Byte]] = {
-    JGitUtil.withGit(Directory.getWikiRepositoryDir(owner, repository)){ git =>
+    using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
       if(!JGitUtil.isEmpty(git)){
         val index = path.lastIndexOf('/')
         val parentPath = if(index < 0) "."  else path.substring(0, index)
@@ -82,7 +83,7 @@
    * Returns the list of wiki page names.
    */
   def getWikiPageList(owner: String, repository: String): List[String] = {
-    JGitUtil.withGit(Directory.getWikiRepositoryDir(owner, repository)){ git =>
+    using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
       JGitUtil.getFileList(git, "master", ".")
         .filter(_.name.endsWith(".md"))
         .map(_.name.replaceFirst("\\.md$", ""))
@@ -102,7 +103,7 @@
       cloneOrPullWorkingCopy(workDir, owner, repository)
 
       // write as file
-      JGitUtil.withGit(workDir){ git =>
+      using(Git.open(workDir)){ git =>
         val file = new File(workDir, newPageName + ".md")
         val added = if(!file.exists || FileUtils.readFileToString(file, "UTF-8") != content){
           FileUtils.writeStringToFile(file, content, "UTF-8")
@@ -145,7 +146,7 @@
       // delete file
       new File(workDir, pageName + ".md").delete
     
-      JGitUtil.withGit(workDir){ git =>
+      using(Git.open(workDir)){ git =>
         git.rm.addFilepattern(pageName + ".md").call
     
         // commit and push
@@ -164,7 +165,7 @@
           .call
       git.getRepository.close  // close .git resources.
     } else {
-      JGitUtil.withGit(workDir){ git =>
+      using(Git.open(workDir)){ git =>
         git.pull.call
       }
     }
diff --git a/src/main/scala/servlet/GitRepositoryServlet.scala b/src/main/scala/servlet/GitRepositoryServlet.scala
index 73b5f7e..944363d 100644
--- a/src/main/scala/servlet/GitRepositoryServlet.scala
+++ b/src/main/scala/servlet/GitRepositoryServlet.scala
@@ -10,10 +10,10 @@
 import javax.servlet.ServletContext
 import javax.servlet.http.HttpServletRequest
 import util.{JGitUtil, Directory}
+import util.ControlUtil._
 import service._
 import WebHookService._
-import org.eclipse.jgit.diff.DiffEntry
-import org.apache.http.client.methods.HttpPost
+import org.eclipse.jgit.api.Git
 
 /**
  * Provides Git repository via HTTP.
@@ -80,7 +80,7 @@
   private val logger = LoggerFactory.getLogger(classOf[CommitLogHook])
   
   def onPostReceive(receivePack: ReceivePack, commands: java.util.Collection[ReceiveCommand]): Unit = {
-    JGitUtil.withGit(Directory.getRepositoryDir(owner, repository)) { git =>
+    using(Git.open(Directory.getRepositoryDir(owner, repository))) { git =>
       commands.asScala.foreach { command =>
         val commits = JGitUtil.getCommitLog(git, command.getOldId.name, command.getNewId.name)
         val refName = command.getRefName.split("/")
diff --git a/src/main/scala/util/Directory.scala b/src/main/scala/util/Directory.scala
index 73cee55..5409962 100644
--- a/src/main/scala/util/Directory.scala
+++ b/src/main/scala/util/Directory.scala
@@ -1,6 +1,7 @@
 package util
 
 import java.io.File
+import util.ControlUtil._
 
 /**
  * Provides directories used by GitBucket.
@@ -21,17 +22,17 @@
   /**
    * Repository names of the specified user.
    */
-  def getRepositories(owner: String): List[String] = {
-    val dir = new File(s"${RepositoryHome}/${owner}")
-    if(dir.exists){
-      dir.listFiles.filter { file =>
-        file.isDirectory && !file.getName.endsWith(".wiki.git") 
-      }.map(_.getName.replaceFirst("\\.git$", "")).toList
-    } else {
-      Nil
+  def getRepositories(owner: String): List[String] =
+    defining(new File(s"${RepositoryHome}/${owner}")){ dir =>
+      if(dir.exists){
+        dir.listFiles.filter { file =>
+          file.isDirectory && !file.getName.endsWith(".wiki.git")
+        }.map(_.getName.replaceFirst("\\.git$", "")).toList
+      } else {
+        Nil
+      }
     }
-  }
-  
+
   /**
    * Substance directory of the repository.
    */
diff --git a/src/main/scala/util/FileUtil.scala b/src/main/scala/util/FileUtil.scala
index 1c35444..fad4067 100644
--- a/src/main/scala/util/FileUtil.scala
+++ b/src/main/scala/util/FileUtil.scala
@@ -4,19 +4,18 @@
 import java.net.URLConnection
 import java.io.File
 import org.apache.commons.compress.archivers.zip.{ZipArchiveEntry, ZipArchiveOutputStream}
+import util.ControlUtil._
 
 object FileUtil {
   
-  def getMimeType(name: String): String = {
-    val fileNameMap = URLConnection.getFileNameMap()
-    val mimeType = fileNameMap.getContentTypeFor(name)
-    if(mimeType == null){
-      "application/octet-stream"
-    } else {
-      mimeType
+  def getMimeType(name: String): String =
+    defining(URLConnection.getFileNameMap()){ fileNameMap =>
+      fileNameMap.getContentTypeFor(name) match {
+        case null     => "application/octet-stream"
+        case mimeType => mimeType
+      }
     }
-  }
-  
+
   def isImage(name: String): Boolean = getMimeType(name).startsWith("image/")
   
   def isLarge(size: Long): Boolean = (size > 1024 * 1000)
@@ -36,21 +35,15 @@
       }
     }
 
-    val out = new ZipArchiveOutputStream(dest)
-    try {
+    using(new ZipArchiveOutputStream(dest)){ out =>
       addDirectoryToZip(out, dir, dir.getName)
-    } finally {
-      IOUtils.closeQuietly(out)
     }
   }
 
-  def getExtension(name: String): String = {
-    val index = name.lastIndexOf('.')
-    if(index >= 0){
-      name.substring(index + 1)
-    } else {
-      ""
+  def getExtension(name: String): String =
+    name.lastIndexOf('.') match {
+      case i if(i >= 0) => name.substring(i + 1)
+      case _ => ""
     }
-  }
 
 }
\ No newline at end of file
diff --git a/src/main/scala/util/Implicits.scala b/src/main/scala/util/Implicits.scala
index 388f9f6..5d8f77b 100644
--- a/src/main/scala/util/Implicits.scala
+++ b/src/main/scala/util/Implicits.scala
@@ -12,7 +12,7 @@
     def splitWith(condition: (A, A) => Boolean): Seq[Seq[A]] = split(seq)(condition)
 
     @scala.annotation.tailrec
-    private def split[A](list: Seq[A], result: Seq[Seq[A]] = Nil)(condition: (A, A) => Boolean): Seq[Seq[A]] = {
+    private def split[A](list: Seq[A], result: Seq[Seq[A]] = Nil)(condition: (A, A) => Boolean): Seq[Seq[A]] =
       list match {
         case x :: xs => {
           xs.span(condition(x, _)) match {
@@ -21,7 +21,6 @@
         }
         case Nil => result
       }
-    }
   }
 
   implicit class RichString(value: String){
diff --git a/src/main/scala/util/JGitUtil.scala b/src/main/scala/util/JGitUtil.scala
index 9114364..3878736 100644
--- a/src/main/scala/util/JGitUtil.scala
+++ b/src/main/scala/util/JGitUtil.scala
@@ -3,6 +3,7 @@
 import org.eclipse.jgit.api.Git
 import util.Directory._
 import util.StringUtil._
+import util.ControlUtil._
 import scala.collection.JavaConverters._
 import org.eclipse.jgit.lib._
 import org.eclipse.jgit.revwalk._
@@ -113,24 +114,6 @@
   case class TagInfo(name: String, time: Date, id: String)
 
   /**
-   * Use this method to use the Git object.
-   * Repository resources are released certainly after processing.
-   */
-  def withGit[T](dir: java.io.File)(f: Git => T): T = withGit(Git.open(dir))(f)
-  
-  /**
-   * Use this method to use the Git object.
-   * Repository resources are released certainly after processing.
-   */
-  def withGit[T](git: Git)(f: Git => T): T = {
-    try {
-      f(git)
-    } finally {
-      git.getRepository.close
-    }
-  }
-  
-  /**
    * Returns RevCommit from the commit or tag id.
    * 
    * @param git the Git object
@@ -151,7 +134,7 @@
    * Returns the repository information. It contains branch names and tag names.
    */
   def getRepositoryInfo(owner: String, repository: String, baseUrl: String): RepositoryInfo = {
-    withGit(getRepositoryDir(owner, repository)){ git =>
+    using(Git.open(getRepositoryDir(owner, repository))){ git =>
       try {
         // get commit count
         val commitCount = git.log.all.call.iterator.asScala.map(_ => 1).take(1000).sum
@@ -370,11 +353,8 @@
     if(large == false && FileUtil.isLarge(loader.getSize)){
       None
     } else {
-      val db = git.getRepository.getObjectDatabase
-      try {
+      using(git.getRepository.getObjectDatabase){ db =>
         Some(db.open(id).getBytes)
-      } finally {
-        db.close
       }
     }
   } catch {
@@ -483,12 +463,9 @@
   }
 
   def initRepository(dir: java.io.File): Unit = {
-    val repository = new RepositoryBuilder().setGitDir(dir).setBare.build
-    try {
+    using(new RepositoryBuilder().setGitDir(dir).setBare.build){ repository =>
       repository.create
       setReceivePack(repository)
-    } finally {
-      repository.close
     }
   }