How to create an executable helloworld.jar
Let’s say you’re in the final stage for a job.
You’re instructed to create an executable jar file whose main method prints hello, world following a line separator. And you have 600 seconds to do that.
If you think about ant, maven, or gradle, you’re already late.
edit HelloWorld.java
$ vi HelloWorld.java
$ cat HelloWorld.java
public class HelloWorld {
public static void main(final String... args) {
System.out.printf("hello, world%n");
}
}
$ javac HelloWorld.java
java HelloWorld
hello, world
edit HelloWorld.mf
$ vi HelloWorld.mf $ cat HelloWorld.mf Main-Class: HelloWorld $
create the jar
$ jar cmf HelloWorld.mf helloworld.jar HelloWorld.class $ java -jar helloworld.jar hello, world $
How fast can you do that?
