** This project was originally developed on replit. https://replit.com/@raymond-chetty/JavaBazelTemplate0 This is a port to github with some modifications. Updates pending.

** DUE TO ISSUES WITH REPLIT THIS PROJECT HAS NOT BEEN TESTED.

A 0 dependency replit template project for java using the bazel build system.

Documentation about java and bazel can be found at the bazel website

• https://bazel.build/docs/bazel-and-java
• https://bazel.build/start/java
• https://bazel.build/docs/external#external-packages

Documentation about the java programming language is available on the oracle website.

• https://docs.oracle.com/en/java/javase/19/
• https://docs.oracle.com/javase/specs/jls/se19/html/index.html

This project uses three main software components, Java, Bazel, and bazelisk. The supported versions for this template is as follows:

This version is configured in a few places:

• remote_oraclejdk_linux.bzl contains the rules and macros that are added to the BUILD and WORKSPACE in order to download and use oracle java. It is possible to switch to JAVA 17.0.5 (LTS) by changing DEFAULT_JAVA_VERSION=17 in this file. The default value is 19.

  TODO: Document oracle java configuration

• .bazelrc configures the default behavior for the build, test, and run bazel commands. It sets the java version for runtime, compilation, and testing.

These above configurations define what version of JAVA is used to run a java binary or to compile your java source code using bazel and bazelisk. This is different from the java version used to run java and javac at the commandline. This project uses replit.nix to provision java for use on the command line within replit. bazel and bazelisk use this version as a @local_jdk and it seems to be required for proper functionality.

The default java installed within replit is JAVA 11.0.15 from OpenJDK using pkgs.jdk11_headless as the package.

https://search.nixos.org/packages?query=jdk11_headless

This version is defined in the .bazeliskrc file.

Bazelisk downloads and aliases the defined version bazel that is configured in .bazeliskrc using the variable USE_BAZEL_VERSION.

This version is defined in the replit.nix file.

https://search.nixos.org/packages?query=bazelisk

All versions listed are the current latests available on the platforms provided by replit, nixOS, bazel, and oracle. The nixOS package versions are defined by the nixOS 22.05 release.

https://nixos.org/blog/announcements.html#nixos-22.05

Changes to the versions of any of these pieces of software may break certain functionality of the build. Due to how replit provisions the environments, using nixOS, it is possible that the bazelisk and openJDK11 versions will change when upgrading. That said, the BAZEL version is defined in the build configurations and should be stable over time.

The .replit file defines the 'compile' and 'run' commands that power the green "Run" button. Due to some unkown reason bazel isn't able to run on occasion, every other run. So it may become necessary to kill the running bazel process or cancel the stalled build command from the command line. It is suggeted that you only initiate builds or runs from the command line.

To run bazel in a replit container

$ bazel run @//:Main 

To get verbose output when running use the following

$ bazel run @//:Main --verbose_failures

If the build stalls at the command line with no output press CTRL-C three times.

This project is configured to use pinned dependency versions of its java artifacts which are retrieved from maven repositories. Bazel uses 'rules_jvm_external' to configure repositories and declare dependencies, this configuration can be found in the 'WORKSPACE' file. The 'BUILD' file defines which dependencies are used during the build process.

The pinned dependency versions are stored in 'maven_install.json' and must be updated after configuration changes in order to successfully run the build with bazel.

To update maven_install.json, run this command to re-pin the unpinned repository:

$ bazel run @unpinned_maven//:pin

The initial file was created with the following:

$ bazel run @maven//:pin

For additional information about 'rules_jvm_external' see the project on github. https://github.com/bazelbuild/rules_jvm_external#pinning-artifacts-and-integration-with-bazels-downloader

There is a new dependency management system for bazel, bzlmod, which doesn't appear to have many available java packages currently. This template doesn't use bzlmod. bzlmod dependencies can be found in 'MODULE.bazel'. Additional information about bzlmod and dependencies generally can be found at the bazel website.

• https://bazel.build/basics/dependencies
• https://bazel.build/build/bzlmod
• https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html

• https://junit.org/junit5/