Delete directories recursively in Java

Question

Is there a way to delete entire directories recursively in Java   In the normal case it is possible to delete an empty directory  However when it comes to deleting entire directories with contents  it is not that simple anymore   How do you delete entire directories with contents in Java

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While files can easily be deleted using file delete    directories are required to be empty to be deleted  Use recursion to do this easily  For example    public static void clearFolders String   args            for String st   args               File folder   new File st               if  folder isDirectory                      File   files   folder listFiles                    if files  null                         for File f  files                            if  f isDirectory                                 clearFolders new String   f getAbsolutePath                                  f delete                              else                               f delete

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i coded this routine that has 3 safety criteria for safer use   package ch ethz idsc queuey util   import java io File  import java io IOException       recursive file directory deletion        safety from erroneous use is enhanced by three criteria    1  checking the depth of the directory tree T to be deleted    against a permitted upper bound  max depth     2  checking the number of files to be deleted  F    against a permitted upper bound  max count     3  if deletion of a file or directory fails  the process aborts    public final class FileDelete           Example  The command        FileDelete of new File   user name myapp recordings log20171024    2  1000          deletes given directory with sub directories of depth of at most 2         and max number of total files less than 1000  No files are deleted        if directory tree exceeds 2  or total of files exceed 1000                 abort criteria are described at top of class                 param file         param max depth         param max count         return         throws Exception if criteria are not met        public static FileDelete of File file  int max depth  int max count  throws IOException           return new FileDelete file  max depth  max count                 ---     private final File root      private final int max depth      private int removed   0            param root file or a directory  If root is a file  the file will be deleted                    If root is a directory  the directory tree will be deleted          param max depth of directory visitor         param max count of files to delete         throws IOException        private FileDelete final File root  final int max depth  final int max count  throws IOException           this root   root          this max depth   max depth             ---         final int count   visitRecursively root  0  false           if  count  lt   max count     abort criteria 2              visitRecursively root  0  true           else             throw new IOException  more files to be deleted than allowed      max count     lt      count      in     root              private int visitRecursively final File file  final int depth  final boolean delete  throws IOException           if  max depth  lt  depth     enforce depth limit  abort criteria 1              throw new IOException  directory tree exceeds permitted depth               ---         int count   0          if  file isDirectory       if file is a directory  recur             for  File entry   file listFiles                    count    visitRecursively entry  depth   1  delete             count     count file as visited         if  delete                final boolean deleted   file delete                if   deleted     abort criteria 3                  throw new IOException  cannot delete     file getAbsolutePath                   removed                    return count             public int deletedCount             return removed             public void printNotification             int count   deletedCount            if  0  lt  count              System out println  deleted     count     file s  in     root

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In Java 7  you can use Files class  Code is very simple   Path directory   Paths get   tmp    Files walkFileTree directory  new SimpleFileVisitor lt Path gt          Override    public FileVisitResult visitFile Path file  BasicFileAttributes attrs  throws IOException          Files delete file          return FileVisitResult CONTINUE            Override    public FileVisitResult postVisitDirectory Path dir  IOException exc  throws IOException          Files delete dir          return FileVisitResult CONTINUE

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Two ways to fail with symlinks and the above code    and don t know the solution   Way  1  Run this to create a test   echo test   testfile mkdir dirtodelete ln -s badlink dirtodelete badlinktodelete   Here you see your test file and test directory     ls testfile dirtodelete testfile  dirtodelete  linktodelete  Then run your commons-io deleteDirectory    It crashes saying the file is not found  Not sure what the other examples do here  The Linux rm command would simply delete the link  and rm -r on the directory would also   Exception in thread  main  java io FileNotFoundException  File does not exist   tmp dirtodelete linktodelete  Way  2  Run this to create a test   mkdir testdir echo test   testdir testfile mkdir dirtodelete ln -s    testdir dirtodelete dirlinktodelete   Here you see your test file and test directory     ls dirtodelete testdir dirtodelete  dirlinktodelete  testdir  testfile   Then run your commons-io deleteDirectory   or the example code people posted  It deletes not only the directory  but your testfile which is outside the directory being deleted   It dereferences the directory implicitly  and deletes the contents   rm -r would delete the link only  You need to use something like this delete the dereferenced files   find -L dirtodelete -type f -exec rm            ls dirtodelete testdir ls  cannot access dirtodelete  No such file or directory testdir

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Guava provides a one-liner  MoreFiles deleteRecursively     Unlike many of the examples shared  it accounts for symbolic links and will not  by default  delete files outside the provided path

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You could use   org apache commons io FileUtils deleteQuietly destFile    Deletes a file  never throwing an exception  If file is a directory  delete it and all sub-directories   The difference between File delete   and this method are   A directory to be deleted does not have to be empty   No exceptions are thrown when a file or directory cannot be deleted

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One-liner solution  Java8  to delete all files and directories recursively including starting directory   Files walk Paths get  c  dir to delete                      map Path  toFile                   sorted  o1  o2  - gt  -o1 compareTo o2                    forEach File  delete     We use a comparator for reversed order  otherwise File  delete won t be able to delete possibly non-empty directory  So  if you want to keep directories and only delete files just remove the comparator in sorted   or remove sorting completely and add files filter   Files walk Paths get  c  dir to delete                      filter Files  isRegularFile                   map Path  toFile                   forEach File  delete

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Just saw my solution is more or less the same as erickson s  just packaged as a static method  Drop this somewhere  it s much lighter weight than installing all of Apache Commons for something that  as you can see  is quite simple   public class FileUtils                  By default File delete fails for non-empty directories  it works like  rm           We need something a little more brutual - this does the equivalent of  rm -r          param path Root File Path         return true iff the file and all sub files directories have been removed         throws FileNotFoundException             public static boolean deleteRecursive File path  throws FileNotFoundException          if   path exists    throw new FileNotFoundException path getAbsolutePath             boolean ret   true          if  path isDirectory                 for  File f   path listFiles                     ret   ret  amp  amp  deleteRecursive f                                   return ret  amp  amp  path delete

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With Java 7  we can finally do this with reliable symlink detection   I don t consider Apache s commons-io to have reliable symlink detection at this time  as it doesn t handle links on Windows created with mklink    For the sake of history  here s a pre-Java 7 answer  which follows symlinks   void delete File f  throws IOException     if  f isDirectory          for  File c   f listFiles          delete c         if   f delete        throw new FileNotFoundException  Failed to delete file      f

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You should check out Apache s commons-io   It has a FileUtils class that will do what you want   FileUtils deleteDirectory new File  directory

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In legacy projects  I need to create native Java code  I create this code similar to Paulitex code  See that   public class FileHelper       public static boolean delete File fileOrFolder          boolean result   true        if fileOrFolder isDirectory               for  File file   fileOrFolder listFiles                  result   result  amp  amp  delete file                            result   result  amp  amp  fileOrFolder delete          return result            And the unit test   public class FileHelperTest         Before     public void setup   throws IOException          new File  FOLDER TO DELETE SUBFOLDER   mkdirs           new File  FOLDER TO DELETE SUBFOLDER TWO   mkdirs           new File  FOLDER TO DELETE SUBFOLDER TWO TEST FILE txt   createNewFile                Test     public void deleteFolderWithFiles            File folderToDelete   new File  FOLDER TO DELETE           Assert assertTrue FileHelper delete folderToDelete           Assert assertFalse new File  FOLDER TO DELETE   exists

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Without Commons IO and   lt  Java SE 7   public static void deleteRecursive File path               path listFiles new FileFilter                      Override                 public boolean accept File pathname                        if  pathname isDirectory                              pathname listFiles this                           pathname delete                          else                           pathname delete                                              return false                                                path delete

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Java 7 added support for walking directories with symlink handling   import java nio file     public static void removeRecursive Path path  throws IOException       Files walkFileTree path  new SimpleFileVisitor lt Path gt                   Override         public FileVisitResult visitFile Path file  BasicFileAttributes attrs                  throws IOException                       Files delete file               return FileVisitResult CONTINUE                      Override         public FileVisitResult visitFileFailed Path file  IOException exc  throws IOException                          try to delete the file anyway  even if its attributes                could not be read  since delete-only access is                theoretically possible             Files delete file               return FileVisitResult CONTINUE                      Override         public FileVisitResult postVisitDirectory Path dir  IOException exc  throws IOException                       if  exc    null                                Files delete dir                   return FileVisitResult CONTINUE                            else                                  directory iteration failed  propagate exception                 throw exc                                      I use this as a fallback from platform-specific methods  in this untested code    public static void removeDirectory Path directory  throws IOException          does nothing if non-existent     if  Files exists directory                 try                          prefer OS-dependent directory removal tool             if  SystemUtils IS OS WINDOWS                  Processes execute   ComSpec      C    RD  S  Q       directory                     else if  SystemUtils IS OS UNIX                  Processes execute   bin rm    -rf   directory toString                       catch  ProcessExecutionException   InterruptedException e                           fallback to internal implementation on error                    if  Files exists directory               removeRecursive directory              SystemUtils is from Apache Commons Lang  Processes is private but its behavior should be obvious

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A solution with a stack and without recursive methods   File dir   new File   path to dir    File   currList  Stack lt File gt  stack   new Stack lt File gt     stack push dir   while    stack isEmpty          if  stack lastElement   isDirectory              currList   stack lastElement   listFiles            if  currList length  gt  0                for  File curr  currList                    stack push curr                           else               stack pop   delete                    else           stack pop   delete

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Below code recursively delete all contents  in a given folder       boolean deleteDirectory File directoryToBeDeleted        File   allContents   directoryToBeDeleted listFiles        if  allContents    null            for  File file   allContents                deleteDirectory file                       return directoryToBeDeleted delete

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Guava had Files deleteRecursively File  supported until Guava 9   From Guava 10      Deprecated  This method suffers from poor symlink detection and race conditions  This functionality can be supported suitably only by shelling out to an operating system command such as rm -rf or del  s  This method is scheduled to be removed from Guava in Guava release 11 0    Therefore  there is no such method in Guava 11

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rm -rf was much more performant than FileUtils deleteDirectory   After extensive benchmarking  we found that using rm -rf was multiple times faster than using FileUtils deleteDirectory    Of course  if you have a small or simple directory  it won t matter but in our case we had multiple gigabytes and deeply nested sub directories where it would take over 10 minutes with FileUtils deleteDirectory and only 1 minute with rm -rf   Here s our rough Java implementation to do that       Delete directory given and all subdirectories and files  i e  recursively      static public boolean deleteDirectory  File file   throws IOException  InterruptedException        if   file exists                String deleteCommand    rm -rf     file getAbsolutePath            Runtime runtime   Runtime getRuntime             Process process   runtime exec  deleteCommand            process waitFor             return true             return false       Worth trying if you re dealing with large or complex directories

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Well  let s assume an example   import java io File  import java io IOException   public class DeleteDirectory      private static final String folder    D  project java       public static void main String   args  throws IOException            File fl   new File folder         if  fl exists       checking if directory exists                  System out println  Sorry   directory doesn t exist                   else                  DeleteDirectory dd   new DeleteDirectory             dd deleteDirectory fl                    public void deleteDirectory File file  throws IOException            if file isDirectory                     if file list   length    0                          deleteEmptyDirectory file      here if directory is empty delete we are deleting                     else                        File fe     file listFiles                for File deleteFile   fe                               deleteDirectory deleteFile      recursive call                           if file list   length    0                               deleteEmptyDirectory file                                          else                  file delete             System out println  File deleted       file getAbsolutePath                      private void deleteEmptyDirectory File fi             fi delete          System out println  Directory deleted       fi getAbsolutePath              For more information refer below resources  Delete directory

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for Path p   Files walk directoryToDelete           sorted  a  b  - gt  b compareTo a       reverse  files before dirs         toArray Path    new         Files delete p       Or if you want to handle the IOException   Files walk directoryToDelete       sorted  a  b  - gt  b compareTo a       reverse  files before dirs     forEach p - gt            try   Files delete p             catch IOException e

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An optimal solution that handles exception consistently with the approach that an exception thrown from a method should always describe what that method was trying  and failed  to do   private void deleteRecursive File f  throws Exception       try           if  f isDirectory                  for  File c   f listFiles                      deleteRecursive c                                   if   f delete                  throw new Exception  Delete command returned false for file      f                        catch  Exception e            throw new Exception  Failed to delete the folder      f  e

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If you have Spring  you can use FileSystemUtils deleteRecursively   import org springframework util FileSystemUtils   boolean success   FileSystemUtils deleteRecursively new File  directory

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Maybe a solution for this problem might be to reimplement the delete method of the File class using the code from erickson s answer   public class MyFile extends File           lt - copy constructor    public boolean delete         if  f isDirectory            for  File c   f listFiles              return new MyFile c  delete                  else           return f delete

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static public void deleteDirectory File path         if  path    null          return      if  path exists                  for File f   path listFiles                          if f isDirectory                                   deleteDirectory f                   f delete                              else                               f delete                                    path delete

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Java 8 with lambda  amp  stream  if param is directory static boolean delRecursive File dir        return Arrays stream dir listFiles    allMatch  f  - gt  f isDirectory     delRecursive f    f delete     amp  amp  dir delete          if param is file or directory static boolean delRecursive File fileOrDir        return fileOrDir isDirectory     Arrays stream fileOrDir listFiles    allMatch  f  - gt  delRecursive f    amp  amp  fileOrDir delete     fileOrDir delete

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Here is a bare bones main method that accepts a command line argument  you may need to append your own error checking or mold it to how you see fit   import java io File  import java io FileNotFoundException  import java io IOException   public class DeleteFiles            param intitial arguments take in a source to read from and a     destination to read to         public static void main String   args                       throws FileNotFoundException IOException           File src   new File args 0            if   src exists                   System out println  FAILURE              else                 Gathers files in directory             File   a   src listFiles                for  int i   0  i  lt  a length  i                        Sends files to recursive deletion method                 fileDelete a i                                 Deletes original source folder             src delete                System out println  Success                                      param srcFile Source file to examine         throws FileNotFoundException if File not found         throws IOException if File not found             private static void fileDelete File srcFile                       throws FileNotFoundException  IOException              Checks if file is a directory         if  srcFile isDirectory                    Gathers files in directory             File   b   srcFile listFiles                for  int i   0  i  lt  b length  i                        Recursively deletes all files and sub-directories                 fileDelete b i                                 Deletes original sub-directory file             srcFile delete              else               srcFile delete                        I hope that helps

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public void deleteRecursive File path       File   c   path listFiles        System out println  Cleaning out folder     path toString         for  File file   c           if  file isDirectory                 System out println  Deleting file     file toString                 deleteRecursive file               file delete              else               file delete                        path delete

[java] Delete directories recursively in Java

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