java extract jar file on MacOS

if you meet error like this:

java.io.IOException: META-INF : could not create directory

at sun.tools.jar.Main.extractFile(Main.java:1050)

at sun.tools.jar.Main.extract(Main.java:981)

at sun.tools.jar.Main.run(Main.java:311)

at sun.tools.jar.Main.main(Main.java:1288)

It might be that you didn'y have rights to write the file. So we need to do like this:

sudo -s

sudo mount -o rw

the 

jar xvf ... .jar