$ git clone git://github.com/kwart/jd-cmd.git

$ cd jd-cmd
$ mvn clean package

$ java -jar jd-cli/target/jd-cli.jar

Usage: java -jar jd-cli.jar [options] [Files to decompile]
  Options:
    --displayLineNumbers, -n
       Include line numbers in decompiled classes
       Default: false
    --help, -h
       Show this help
       Default: false
    --logLevel, -g
       Log level, one of: ALL, TRACE, DEBUG, INFO, WARN, ERROR, OFF
       Default: INFO
    --outputConsole, -oc
       Output to system output stream
       Default: false
    --outputDir, -od
       Output to a directory with given path
    --outputZipFile, -oz
       Output to a zipped file with given path
    --showLocation, -l
       Include Location info in decompiled classes metadata part
       Default: false
    --skipMetadata, -sm
       Don't include metadata in decompiled classes
       Default: false
    --skipResources, -sr
       Skip processing resources
       Default: false

import java.io.File;
import jd.core.input.JDInput;
import jd.core.input.ZipFileInput;
import jd.core.output.DirOutput;
import jd.core.output.JDOutput;
import jd.ide.intellij.JavaDecompiler;

public class App {
	public static void main(String[] args) {
		JavaDecompiler javaDecompiler = new JavaDecompiler();
		//choose input plugin for your decompiled file (class, zip, directory)
		JDInput jdIn = new ZipFileInput("path/to/myFavorityLib.jar");
		//choose output plugin (zip, directory, console)
		JDOutput jdOut = new DirOutput(new File("/tmp/decompiled"));
		//decompile
		jdIn.decompile(javaDecompiler, jdOut);
	}
}