Find a jar file given the class name?

Question

This must be a very basic question for Java developers, but what is the best way to find the appropriate jar file given a class name?

For example, given "com.ibm.websphere.security.auth.WSSubject", how do you track down the appropriate jar file? ("google" is not the answer I'm looking for!)

The java docs do not give any hint of the jar file, and obviously the names of the jar files themselves offer no clue.

There must be a 'search local jars', or some sort of 'auto-resolve dependencies', trick in the java world. Ideally, I'm looking for the 'official' way to do this. I happen to be on a windows machine without cygwin.

Answer 1

Save this as findclass.sh (or whatever), put it on your path and make it executable:

#!/bin/sh
find "$1" -name "*.jar" -exec sh -c 'jar -tf {}|grep -H --label {} '$2'' \;

The first parameter is the directory to search recursively and the second parameter is a regular expression (typically just a simple class name) to search for.

$ findclass.sh . WSSubject

The script relies on the -t option to the jar command (which lists the contents) and greps each table of contents, labelling any matches with the path of the JAR file in which it was found.

Answer 2

There is no "official" Java way to do this AFAIK.

The way I usually hunt for it is to use find and jar to look through all jar files in a given tree.

> find . -name \*.jar -print -exec jar tf {} oracle/sql/BLOB.class \;
./v2.6.1/lib/csw_library.jar
./v2.6.1/lib/oracle_drivers_12_01.jar
oracle/sql/BLOB.class

If you're on Windows and don't want to install Cygwin, then I suppose you would have to write a batch script to locate the jar files.

Answer 3

I have written a program for this: https://github.com/javalite/jar-explorer It will also decompile existing byte code to show you interfaces, methods, super classes, will show contents of other resources - text, images, html, etc.

Answer 4

To search all jars under the current directory and return the one(s) that contain class a.b.c.D do a:

find . -iname *.jar | while read JARF; do jar tvf $JARF | grep a/b/c/D.class && echo $JARF ; done

It will report all instances of class a.b.c.D (or classes with a similar suffix) and will only print the jars that contain it.

Typical output:

$ find . -iname *.jar | while read JARF; do jar tvf $JARF | grep Log.class && echo $JARF ; done
479 Fri Oct 10 18:19:40 PDT 2003 org/apache/commons/logging/Log.class
3714 Fri Oct 10 18:19:40 PDT 2003 org/apache/commons/logging/impl/Log4JCategoryLog.class
1963 Fri Oct 10 18:19:40 PDT 2003 org/apache/commons/logging/impl/NoOpLog.class
9065 Fri Oct 10 18:19:40 PDT 2003 org/apache/commons/logging/impl/SimpleLog.class
./WebContent/WEB-INF/lib/commons-logging.jar

Answer 5

You could try services like:

• http://www.jarhoo.com/
• http://www.docjar.com/
• http://javacio.us/
• http://merobase.com/

Or

• Google Desktop with the Airbear Software's IndexZip Plug-in

Or

• A maven enterprise repository with a search feature e.g. Nexus (OFC, this would only work if the jars you're looking for are indexed i.e. installed in the repository)

PS: Jarhoo has teamed up with Javacio.us to provide 100,000 Java developers with free access to Jarhoo via links integrated with their Google search results. Subscription to Javacio.us is free and open to anyone with a Google account. For more information, please visit the Jarhoo offer page at Javacio.us.

Answer 6

If the grep on your system (e.g. Solaris) doesn't have -H and --label as used in Dan Dyer's example, you can use:

find . -name '*.jar' -type f | xargs -i bash -c "jar -tvf {}| tr / . | grep WSSubject && echo {}"

Answer 7

In Windows, run cmd.exe and type:

  for %i in (*.jar) do @jar tvf %i | find "/com/company/MyClass.class"

The jars would have to be in the current directory. For also has a /R option which takes a directory and lets you search recursively.

If Jar.exe isn't in your path, you can do something like @C:\jdk\bin\jar.exe.

Answer 8

Try findjar.com. If it's in the public domain, you should get it. There's alos mavenjava.com (but that site seems to be down)

Answer 9

Printing the list as I go so I can see what I'm checking. Mostly I'm looking in a lib/app directory, but you can substitute a locate for the find.

e.g.

for jar in $(find some_dir/lib -name "*.jar" ); 
do
echo -------------$jar-------------------
jar -tf $jar | grep TheNameOfTheClassImLookingFor
done

Answer 10

I use jarscan. It is an executable jar file that can recursively search an entire folder structure for jars that contain the class that you are looking for. It searches by class name, package name or regex.

Answer 11

Given your comment on attempting to handle dependencies, what I would do is focus on which libraries you are using. Knowing this, you will know what jars have to be on the classpath, and you can pay attention to that. There are also dependency management builders (Maven and Ant being two popular ones) that can package up projects with their dependencies inside. However, in the end, it is up to the developer to know which dependencies they have, and to pay attention to the requirements for those dependencies. This is one reason why using an IDE like Eclipse, and build tools like Maven or Ant are so nice in large projects, as when you have 20 dependencies for a project, that can become pretty unmanageable.

Answer 12

In windows powershell you can use this command. It list all the JAR files it encounters, but it has an extra line that's very easy to spot where it also finds your class.

Get-ChildItem -recurse -Filter *.jar | Foreach {echo $_.fullname; c:\somepath\JDK\BIN\jar tvf $_.fullname | Select-String -pattern "Cabbages.class"}

Answer 13

There is also this web site that seems to be usefull. http://www.findjar.com/

Answer 14

locate .jar | xargs grep com.ibm.websphere.security.auth.WSSubject

Answer 15

I recommend using Maven, Eclipse and m2eclipse.

Step 1 - add specific import

Step 2 - find and download (automatically) desired jar

Answer 16

if you are still searching for WSSubject, then jar is wssec.jar. WSSecurityException class inside sas.jar

Answer 17

Building up on Dan's excellent answer, the following script solves the problem of mangled output in case some of the jars are actually broken symlinks (while at the same time not skipping proper symlinks) It also searches in the current directory if no argument is provided.

#!/usr/bin/env bash

if [[ ($# -ne 1) && ($# -ne 2) ]]
then
    echo "usage is $0 <grep RegEx to look for in contents of jar> [<top-of-folder-hierarchy> or, if missing, current dir]"
else
    REG_EXP=$1
    DIR=${2:-.}
    if [ ! -d $DIR ]; then
        echo "directory [$DIR] does not exist";
        exit 1;
    fi
    find "$DIR" -name "*.jar" -exec sh -c '
    (test -e {})
    exitStatus=$?
    if [ "$exitStatus" -eq 0 ]; then # this is done to avoid broken symlinks
        jar -tf {}|grep -i -H --label {} '$REG_EXP'
    fi
' \;
fi

Answer 18

in Intellij Idea

1. on your class press ctrl+B and after that you can find the jar file.
2. on project bar press scroll from source.
3. you can see the jar file contains the class.