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How to release junixsocket

This is mostly relevant only if you're the project admin or going to fork the project.


llvm and mingw-w64

In order to build for all supported target platforms included in the release, our development machine (the one where we do the compilation), needs to have clang and llvm, as well as x86_64-w64-mingw32-gcc, a GCC compiler binary to allow building for Windows.

On Mac, run the following command.

brew install llvm mingw-w64

If you don't have Homebrew, obtain it from here first. credentials

  1. On, create an OAuth token with write permissions to the repo.
  2. Add the credentials to your keychain

GPG keys

Instructions for macOS

  • Install gpg and helper tools

    brew install gpg gpg2 gpg-agent pinentry-mac

  • Enable pinentry-mac

    This gives a nice GUI for the passphrase, and allows us to store the GPG key passphrase in the macOS keychain)

  • Open or create ~/.gnupg/gpg-agent.conf then add the following line if it doesn't exist yet:

     pinentry-program /usr/local/bin/pinentry-mac
  • Generate a GPG key

     gpg2 --generate-key

    Follow on-screen instructions. Use a long, memorable passphrase.

  • Remember the GPG key ID. Publish the corresponding GPG public key on the GPG keyservers:

     gpg2 --send-key THEKEYID

Build environment for other platforms

Currently, the easiest way to build for other platforms is to have a working Java 9 (or later) environment, Maven 3+ and the junixsocket project ready. Just spin up a virtual machine (or emulator), install Java, Maven and junixsocket, and you should be good to go.

Common tasks

Update changelog, website,

Update junixsocket/src/site/markdown/ with a section for the new version and all noteworthy changes.

Check all mentions (execpet for of the current junixsocket under junixsocket/src/site/markdown, and replace accordingly: grep X.Y.Z src/site/markdown/* | grep -v

Also update the dependency statement in junixsocket/

NOTE: (Replace X.Y.Z with the current version)

Ensure GraalVM native configs are still up-to-date

Run junixsocket-native-graalvm/bin/with-graalvm junixsocket-native-graalvm/bin/build-selftest

If, at the end, you see changes to the json files in junixsocket-native-graalvm/output, review them, modify the json files in junixsocket-{common,tipc,vsock,selftest,...}/src/main/resources/META-INF/native-image accordingly, and add/commit both sets of changes.

Ensure the code is properly formatted and licenses are in place

First, view the LICENSE file and verify that it's up to date. Then run the code formatters and commit.

cd junixsocket
mvn process-sources -Dreformat
# git add / commit here...

Bump project version

cd junixsocket
mvn versions:set -DnewVersion=X.Y.Z
# git add / commit here...

NOTE: (Replace X.Y.Z with the actual new version)

Build native libraries on other supported, common platforms

NOTE: This section can presently be skipped since all targets shipped in junixsocket-native-common cross-compile with -Drelease.

On the target machine, install junixsocket. Make sure you use the very same version as on your development machine from where you do the release!

cd junixsocket
mvn clean install -Dstrict

The platform-dependent nar files should now be available in the local maven repository cache.

Use the provided script to copy the corresponding nar to a project folder:

cd junixsocket
junixsocket-native-prebuilt/bin/ X.Y.Z

NOTE: (Replace X.Y.Z with the actual version)

Now copy the nar files from the target machine to your development computer (from where you do the release). By convention, copy the files to the same folder as on the target machine (junixsocket/junixsocket-native-prebuilt/bin)

On the development computer, install the nar files in the local Maven repository cache:

cd junixsocket
junixsocket-native-prebuilt/bin/ junixsocket-native-prebuilt/nar/*nar

Create binary distribution

This will create a directory, a .tar.gz and a .zip archive, containing the project jars and a script to run the demo classes from the command-line.

cd junixsocket
mvn clean install -Dstrict -Drelease

The files can be found in

  • junixsocket/junixsocket-dist/target/junixsocket-dist-X.Y.Z-bin
  • junixsocket/junixsocket-dist/target/junixsocket-dist-X.Y.Z-bin.tar.gz
  • junixsocket/junixsocket-dist/target/

NOTE: (Replace X.Y.Z with the actual version)

Verify that Selftest works

Run java -jar junixsocket-selftest/target/junixsocket-selftest-X.Y.Z-jar-with-dependencies.jar. It should end with Selftest PASSED.

Also run the selftest with Java 8, e.g.:

/Library/Java/JavaVirtualMachines/1.8.0.jdk/Contents/Home/bin/java -jar junixsocket-selftest/target/junixsocket-selftest-2.9.1-jar-with-dependencies.jar

Run junixsocket-native-graalvm/bin/with-graalvm mvn package -pl junixsocket-selftest-native-image -Dnative (on all native-image supported platforms) to build the GraalVM native-image. Test the native-image by running junixsocket-selftest-native-image/target/junixsocket-selftest-native-image-X.Y.Z.

NOTE: (Replace X.Y.Z with the actual version)

Deploy code to Maven central

Tag the release, push to upstream (i.e., GitHub)

mvn scm:tag

If you need to make a revision afterwards, retag with git tag -f TAG and git push origin TAG --force.

Deploy to staging

cd junixsocket
mvn clean install -Dstrict -Drelease

# after gpgkeyname, specify the key you want to use for signing
mvn deploy -Dstrict -Drelease -Dsigned -Dgpgkeyname=$(git config --get -Dgpg.executable=$(which gpg)

-Dstrict enforces code quality checks to succeed (e.g., spotbugs, checkstyle).

-Drelease makes sure we include all common native binaries in junixsocket-native-common.

-Dsigned enables signing the artifacts with our GPG key.

In case of failures while staging:

If the deployment fails with Remote staging failed: Staging rules failure! and due to No public key: Key with id: (...) was not able to be located on ..., then that means that the GPG key you created above has not been fully distributed among the GPG key servers. Try to manually push to the ones mentioned in the error message, and try again.

For example:

gpg2 --keyserver --send-key THEKEYID

If you get an error Remote staging failed: A message body reader for Java class, and Java type class, and MIME media type text/html was not found, then simply try again; see OSSRH-51097.

Review the deployed artifacts

The URL of the staging repository is The artifacts can be found here.

If you're deploying a -SNAPSHOT version, you can find the artifacts here.

IMPORTANT Double-check that the staged junixsocket-native-common artifact contains all required library binaries (macOS, Linux 64-bit, etc.).

Review selftest on all supported platforms

Download junixsocket-selftest-X.Y.Z-jar-with-dependencies.jar from staging to all supported platforms:

Run java -jar junixsocket-selftest-X.Y.Z-jar-with-dependencies.jar on all supported platforms and supported JDK combinations.

Depending on the platform, it should end with Selftest PASSED or Selftest PASSED WITH ISSUES.

Also check the header, especially the Git properties at the beginning of the output:

  • The version numbers (junixsocket selftest version and should match the expected version number
  • git.dirty should be false
  • should match the new git tag.

Release artifact to Maven Central

IMPORTANT Once released, it cannot be undone! Make sure you verify the staged artifact first!

MAVEN_OPTS="--add-opens java.base/java.util=ALL-UNNAMED" mvn nexus-staging:release -Drelease

NOTE: There can be quite a delay (30 minutes?) until the artifact is deployed in Maven Central.

Release on GitHub

  1. Log in to GitHub, go to Releases -> Draft a new release.

  2. Select the newly created tag (= search for the version).

  3. Release title = “junixsocket” + version>, e.g., “junixsocket X.Y.Z”

  4. Paste changelog contents to text field

  5. Upload binaries: junixsocket-dist/target/junixsocket-dist-X.Y.Z-bin.tar.gz / as well as junixsocket-selftest/target/junixsocket-selftest-X.Y.Z-jar-with-dependencies.jar

  6. Hit “Publish release”

NOTE: (Replace X.Y.Z with the actual version)

Publish website

This builds the Maven site

cd junixsocket

The website should now be inspected at junixsocket/target/staging/index.html

If everything looks good, we can publish it to

mvn scm-publish:publish-scm -Dstrict -Drelease

NOTE: There can be a 10-minute delay until the pages get updated.

FIXME: We currently don't aggregate code coverage from all platforms. Therefore, especially for TIPC and VSOCK support, the coverage reported is misleading.

Prepare next version

mvn versions:set -DnewVersion=X.Y.Z-SNAPSHOT
mvn clean install

NOTE: (Replace X.Y.Z with the actual version)