Java : create jar executable with dependant jars embedded

Question

I have created an executable JAR with the manifest:

Manifest-Version: 1.0
Main-Class: MyClass
Class-Path: lib/ext.jar

I can successfully run this JAR if I have folder lib with dependent ext.jar in the folder of .jar created.

I would like to embed ext.jar in my executable JAR to launch it anywhere I want, without creating lib folder. This would allow the JAR file to be self-contained, including all of its dependencies.

Is there any way to do this?

Answer 1

The default Java class loader cannot find an embedded jar inside a jar file. You will need to set your Java program to use a class loader which can deal with embedded jar files. As fas as I know, I have not seen one in any opensource libraries so you may need to write one yourself.

Alternatively, you can extract all the jar files and combine the the content into a single jar file.

Clean way to combine multiple jars? Preferably using Ant

Answer 2

Java doesn't have out-of-the-box support for embedding a jar within a jar. It can be achieved by writing a custom class loader, or using a tool that's already been written for this purpose: Fat Jar.