jeremywall / java-tzdb-builder

Automated generation of Time Zone Database files used for updating Java installations

Time Zone Database Builder

What is this?

This repo uses a GitHub Action Workflow to periodically check for new Time Zone Database releases. When a new release is found it will download the Time Zone Database release files and generate the artifacts necessary for updating a Java installation's internal Time Zone Database.

The first artifact generated is a rearguard format tarball of the Time Zone Database that can be used as input to tools like ZIUpdater which will update an existing Java installation's internal Time Zone Database.

The second artifact generated is the final tzdb.dat Time Zone Database data file for people who want to skip using tools like ZIUpdater and just download the final tzdb.dat file.

Contents of this repo

• .github/workflows/build-latest-tzdb.yml is the GitHub Action Workflow that checks for new releases and generates the artifacts.
• test is a directory which contains some test Java code used during the build process to test the Time Zone Database.
• releases is a directory which contains the generated artifacts described above after each build of a new Time Zone Database release.
• ziupdater is a directory which contains a cached copy of the ZIUpdater tool which the GitHub Action Workflow script uses to create the final tzdb.dat file.
• last_processed_version is used to track the last version number of the Time Zone Database that was processed to avoid unecessary builds during periodic checks for new releases.
• last_run_timestamp is used to track the last time an update check was performed.

Using the tzdb.dat file

You need to locate and replace the tzdb.dat of your JVM with the updated tzdb.dat files released in this repository and then restart all Java applications on the computer so they can start using the new Time Zone Database. I've also written a simple bash script that makes a best effort attempt to do this.