zb

name	zb
description	Build Java 21+ projects with zb (Zero Dependencies Builder). Use when compiling, building, packaging, or running Java projects that have no external dependencies. Triggers on "build with zb", "zb build", "compile and package", "create executable JAR", or when a .zb configuration file is present in the project. Not for projects requiring Maven/Gradle dependency management.

zb - Zero Dependencies Builder

Build single-module Java 21+ projects into executable JARs without Maven or Gradle.

How to Build

Step 1: Check for zb.sh script

Search for a zb.sh wrapper script in this order — stop at the first match:

1. zb.sh in the project root
2. Glob for **/zb.sh within the project directory tree
3. Glob for **/zb.sh one level above the project (sibling projects)
4. Check ~/bin/zb.sh or ~/.local/bin/zb.sh

If zb.sh is found, skip to Step 3 (zb.sh) — the script handles jar location and execution internally.

If zb.sh is not found, continue to Step 2 to locate zb.jar manually.

Step 2: Find zb.jar (only if zb.sh not found)

Locate zb.jar in this order — stop at the first match:

1. zb.jar in the project root
2. Glob for **/zb.jar within the project directory tree
3. Glob for **/zb.jar one level above the project (sibling projects)
4. Check ~/bin/zb.jar or ~/.local/bin/zb.jar

If neither zb.sh nor zb.jar is found, tell the user to download from github.com/AdamBien/zb.

Step 3: Find the build directory

zb must run from the directory containing the .zb config file (or where one should be generated). In multi-module repos, this is the module subdirectory, not the repo root.

• Glob for .zb files in the project
• cd into the directory containing the .zb file before running zb
• If no .zb exists, run from the directory that contains src/main/java

Step 4: Run the build

With zb.sh:

cd <build-directory> && <path-to-zb.sh>

With zb.jar (fallback):

cd <build-directory> && java -jar <path-to-zb.jar>

Step 5: Verify

Check exit code and output. A successful build prints the number of compiled files. Common errors:

• "Multiple main classes found" — you are in the wrong directory (likely the repo root instead of a module subdirectory)
• Compilation errors — fix the source and rebuild

Source Directory Convention

zb auto-detects sources in order:

1. src/main/java (Maven convention, preferred)
2. src/
3. Current directory .

Resources auto-detected from src/main/resources or current directory.

Entry Point Requirement

The project must have exactly one class with a void main( method (Java 21+ unnamed main).

Configuration (.zb)

Optional .zb properties file in the build directory (auto-generated on first run):

sources.dir=<discovered by zb>
resources.dir=<discovered by zb>
classes.dir=<temp.dir>
jar.dir=zbo/
jar.file.name=app.jar

• <discovered by zb> — auto-detect directory
• <temp.dir> — use temporary directory, cleaned after build

CLI Arguments (Positional)

java -jar zb.jar [sources] [classes] [jar_dir] [jar_file]

Precedence: CLI args > .zb file > defaults.

Output

Default: zbo/app.jar — executable JAR with Main-Class manifest entry.

Run with:

java -jar zbo/app.jar

Constraints

• Java 21+ required
• No external dependency support (no Maven/Gradle dependency resolution)
• Single-module projects only
• Exactly one main class per project

After a Successful Build

If the project has a test/ directory containing *Test.java files, ask the user if they want to run tests with /zunit.