How to get names of classes inside a jar file

Question

I have a JAR file and I need to get the name of all classes inside this JAR file  How can I do that   I googled it and saw something about JarFile or Java ClassLoader but I have no idea how to do it

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You can try   jar tvf jarfile jar    This will be helpful only if your jar is executable i e  in manifest you have defined some class as main class

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Description OF Solution   Eclipse IDE can be used for this by creating a sample java project and add all jars in the Project Build path  STEPS below    Create a sample Eclipse Java project  All all the jars you have in its Build Path CTRL SHIFT T and Type the full class name   Results will be displayed in the window with all the jars having that class  See attached picture

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You can try this    unzip -v  your jar jar   This will be helpful only if your jar is executable i e  in manifest you have defined some class as main class

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You can use the   jar tf example jar

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Below command will list the content of a jar file     command  - unzip -l jarfilename jar   sample o p  -   Archive   hello-world jar   Length      Date    Time    Name ---------  ---------- -----   ----      43161  10-18-2017 15 44   hello-world com ami so search So class      20531  10-18-2017 15 44   hello-world com ami so util SoUtil class ---------                     -------     63692                     2 files  According to manual of unzip      -l     list archive files  short format    The names  uncompressed file sizes and modification dates and times of the specified files are   printed  along with totals  for  all                 files  specified    If UnZip was compiled with OS2 EAS defined  the -l option also lists columns for the sizes of stored OS 2   extended attributes  EAs  and OS 2 access                 control lists  ACLs    In addition  the zipfile comment and individual file comments  if any  are displayed   If a file was   archived from  a  single-case  file  system                  for example  the old MS-DOS FAT file system  and the -L option was given  the filename is converted to lowercase and is   prefixed with a caret

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windows cmd   This would work if you have all te jars in the same directory and execute the below command   for  r  i in     do   jar tvf  i   find  I  search string

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Use this bash script      bin bash  for VARIABLE in   jar do    jar -tf  VARIABLE  grep    class  awk -v arch  VARIABLE   print arch      4   sed  s      g  sed  s       g  sed  s   class  g  done   this will list the classes inside jars in your directory in the form   file1 jar fullyqualifiedclassName file1 jar fullyqualifiedclassName file1 jar fullyqualifiedclassName file1 jar fullyqualifiedclassName file2 jar fullyqualifiedclassName file2 jar fullyqualifiedclassName file2 jar fullyqualifiedclassName   Sample output   commons-io jar org apache commons io ByteOrderMark commons-io jar org apache commons io Charsets commons-io jar org apache commons io comparator AbstractFileComparator commons-io jar org apache commons io comparator CompositeFileComparator commons-io jar org apache commons io comparator DefaultFileComparator commons-io jar org apache commons io comparator DirectoryFileComparator commons-io jar org apache commons io comparator ExtensionFileComparator commons-io jar org apache commons io comparator LastModifiedFileComparator   In windows you can use powershell   Get-ChildItem -File -Filter   jar   ForEach-Object       filename      Name     Write-Host  filename      classes   jar -tf    Name  Select-String -Pattern   class  -CaseSensitive -SimpleMatch     ForEach  line in  classes           write-host  filename      line -replace    class       -replace

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This is a hack I m using   You can use java s autocomplete like this   java -cp path to jar  lt Tab gt    This will give you a list of classes available to pass as the starting class  Of course  trying to use one that has no main file will not do anything  but you can see what java thinks the classes inside the  jar are called

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Maybe you are looking for jar command to get the list of classes in terminal      jar tf    m2 repository org apache spark spark-assembly 1 2 0-SNAPSHOT spark-assembly-1 2 0-SNAPSHOT-hadoop1 0 4 jar  META-INF  META-INF MANIFEST MF org  org apache  org apache spark  org apache spark unused  org apache spark unused UnusedStubClass class META-INF maven  META-INF maven org spark-project spark  META-INF maven org spark-project spark unused  META-INF maven org spark-project spark unused pom xml META-INF maven org spark-project spark unused pom properties META-INF NOTICE   where    -t  list table of contents for archive -f  specify archive file name   Or  just grep above result to see  classes only    jar tf    m2 repository org apache spark spark-assembly 1 2 0-SNAPSHOT spark-assembly-1 2 0-SNAPSHOT-hadoop1 0 4 jar   grep  class org apache spark unused UnusedStubClass class   To see number of classes    jar tvf launcher target usergrid-launcher-1 0-SNAPSHOT jar   grep  class   wc -l 61079

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Unfortunately  Java doesn t provide an easy way to list classes in the  native  JRE  That leaves you with a couple of options   a  for any given JAR file  you can list the entries inside that JAR file  find the  class files  and then determine which Java class each  class file represents  or  b  you can use a library that does this for you   Option  a   Scanning JAR files manually  In this option  we ll fill classNames with the list of all Java classes contained inside a jar file at  path to jar file jar   List lt String gt  classNames   new ArrayList lt String gt     ZipInputStream zip   new ZipInputStream new FileInputStream   path to jar file jar     for  ZipEntry entry   zip getNextEntry    entry    null  entry   zip getNextEntry          if   entry isDirectory    amp  amp  entry getName   endsWith   class                 This ZipEntry represents a class  Now  what class does it represent          String className   entry getName   replace               including   class          classNames add className substring 0  className length   -   class  length                Option  b   Using specialized reflections libraries  Guava  Guava has had ClassPath since at least 14 0  which I have used and liked  One nice thing about ClassPath is that it doesn t load the classes it finds  which is important when you re scanning for a large number of classes   ClassPath cp ClassPath from Thread currentThread   getContextClassLoader     for ClassPath ClassInfo info   cp getTopLevelClassesRecurusive  my package name             Do stuff with classes here        Reflections  I haven t personally used the Reflections library  but it seems well-liked  Some great examples are provided on the website like this quick way to load all the classes in a package provided by any JAR file  which may also be useful for your application   Reflections reflections   new Reflections  my project prefix     Set lt Class lt   extends SomeType gt  gt  subTypes   reflections getSubTypesOf SomeType class    Set lt Class lt   gt  gt  annotated   reflections getTypesAnnotatedWith SomeAnnotation class

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You can use Java jar tool  List the content of jar file in a txt file and you can see all the classes in the jar   jar tvf jarfile jar      -t  list table of contents for archive      -v  generate verbose output on standard output      -f  specify archive file name

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Mac OS  On Terminal  vim  lt your jar location gt   after jar gets opened  press   and pass your class name and hit enter

[java] How to get names of classes inside a jar file?

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