jar commands

Execute a jar (with common args):
java -jar -cp /foo:/foo/bar/* -D... -X... myApp.jar appArg1=foo appArg2=bar

Create a jar (create, output jar file) in the current directory:
jar cf app.jar input-file(s)

Extract a jar (extract, verbose, input jar file) in the current directory:
jar -xvf app.jar

Extract a war in the current directory:
Similar to the jar way.

Update the jar content for some files without recompiling classes :
jar uf myApp.jar file1 foo/file2
The path of external files matters to perform a replace (and not a file adding to another location)