Tìm hiểu Java khá lâu rồi nay mới biết cách build file jar bằng command :)

HowToBuildJarFile.sh

FILE=hello_world
CONTENT=$(cat <<-END
                public class $FILE {
                        public static void main(String[] args) {
                                System.out.println(
                                        "Excuse me, what the fuck!\\\n" +
                                        "U dont know how to build jar by command?"
                                );
                        }
                }
        END
)

printf "${CONTENT}" >$FILE.java
javac $FILE.java

printf "Main-Class: ${FILE}\n" >manifest
jar cfm $FILE.jar manifest $FILE.class

rm $FILE.java \
   $FILE.class \
   manifest