How to clean old dependencies from maven repositories?

Question

I have too many files in .m2 folder where maven stores downloaded dependencies. Is there a way to clean all old dependencies? For example, if there is a dependency with 3 di

Answer 1

It's been more than 6 years since the question was asked, but I didn't find any tool to clean up my repository. So I wrote one myself in python to get rid of old jars. Maybe it will be useful for someone:

from os.path import isdir
from os import listdir
import re
import shutil

dry_run = False #  change to True to get a log of what will be removed
m2_path = '/home/jb/.m2/repository/' #  here comes your repo path
version_regex = '^\d[.\d]*$'


def check_and_clean(path):
    files = listdir(path)
    for file in files:
        if not isdir('/'.join([path, file])):
            return
    last = check_if_versions(files)
    if last is None:
        for file in files:
            check_and_clean('/'.join([path, file]))
    elif len(files) == 1:
        return
    else:
        print('update ' + path.split(m2_path)[1])
        for file in files:
            if file == last:
                continue
            print(file + ' (newer version: ' + last + ')')
            if not dry_run:
                shutil.rmtree('/'.join([path, file]))


def check_if_versions(files):
    if len(files) == 0:
        return None
    last = ''
    for file in files:
        if re.match(version_regex, file):
            if last == '':
                last = file
            if len(last.split('.')) == len(file.split('.')):
                for (current, new) in zip(last.split('.'), file.split('.')):
                    if int(new) > int(current):
                        last = file
                        break
                    elif int(new) < int(current):
                        break
            else:
                return None
        else:
            return None
    return last


check_and_clean(m2_path)

It recursively searches within the .m2 repository and if it finds a catalog where different versions reside it removes all of them but the newest.

Say you have the following tree somewhere in your .m2 repo:

.
└── antlr
    ├── 2.7.2
    │   ├── antlr-2.7.2.jar
    │   ├── antlr-2.7.2.jar.sha1
    │   ├── antlr-2.7.2.pom
    │   ├── antlr-2.7.2.pom.sha1
    │   └── _remote.repositories
    └── 2.7.7
        ├── antlr-2.7.7.jar
        ├── antlr-2.7.7.jar.sha1
        ├── antlr-2.7.7.pom
        ├── antlr-2.7.7.pom.sha1
        └── _remote.repositories

Then the script removes version 2.7.2 of antlr and what is left is:

.
└── antlr
    └── 2.7.7
        ├── antlr-2.7.7.jar
        ├── antlr-2.7.7.jar.sha1
        ├── antlr-2.7.7.pom
        ├── antlr-2.7.7.pom.sha1
        └── _remote.repositories

If any old version, that you actively use, will be removed. It can easily be restored with maven (or other tools that manage dependencies).

You can get a log of what is going to be removed without actually removing it by setting dry_run = False. The output will go like this:

update /org/projectlombok/lombok
1.18.2 (newer version: 1.18.6)
1.16.20 (newer version: 1.18.6)

This means, that versions 1.16.20 and 1.18.2 of lombok will be removed and 1.18.6 will be left untouched.

The file can be found on my github (the latest version).