No matter in Eclipse or IntelijIdea, there are better packaging methods, but in the gradle era, you have to write your own scripts to play JAR packages. The jar package is actually a collection of all class files, as long as we find the output directory at compile time. Note that a temporary class is generated under build/intermediaries/classes/release (debug), which is the path we need. Then, use the Jar tasks predefined in gradle for configuration.