Java hello world in jar with Makefile

Hello.java

public class Hello {
    public static void main(String args[]) {
        System.out.println("hello world");
    }
}

Makefile

PHONY: all clean

all: hello.jar

Hello.class: Hello.java
  javac $^

hello.jar: Hello.class
  jar -cfe $@ Hello $^

clean:
  -rm -f hello.jar Hello.class