Java

JAR Commands

Create, extract, and manage JAR files. Learn about manifest configuration, executable JARs, multi-release JARs, and module packaging.

8 commands

Pro Tips

Use 'jar --create --file app.jar -e Main -C classes .' to create executable JAR with entry point.

Add '--release 17' flag to create multi-release JARs for version-specific code.

Use 'jar --describe-module --file module.jar' to inspect module information.

Common Mistakes

Manifest files must end with a newline or the last attribute will be ignored.

Signing JARs with expired certificates will cause security exceptions at runtime.

Commands

Create JAR file

$ jar --create --file app.jar -C classes .

Create a JAR from compiled classes directory.

Create executable JAR

$ jar --create --file app.jar --main-class com.example.Main -C classes .

Create JAR with entry point for direct execution.

Run JAR file

$ java -jar app.jar

Execute a JAR file with Main-Class manifest entry.

Extract JAR contents

$ jar --extract --file app.jar

Extract all contents from a JAR file.

List JAR contents

$ jar --list --file app.jar

List all files contained in a JAR.

View manifest

$ unzip -p app.jar META-INF/MANIFEST.MF

Display the manifest file from a JAR.

Update JAR contents

$ jar --update --file app.jar -C updated-classes .

Add or update files in an existing JAR.

Describe module JAR

$ jar --describe-module --file module.jar

Show module descriptor information for a modular JAR.