My scenario:
I have a Main.java file that simply does System.out.println("Hello").
I run it by first, compiling with javac Main.java and then excecuting the command java Main.
Now what I want is that instead of printing "Hello", it will print whatever the user wants, but I don't want to change the source code whenever I want a different output. So I replaced the System.out.println("Hello") with System.out.println(${MESSAGE}). But this gives error "Cannot resolve symbol MESSAGE".
Ultimately, I want a Main.class file and run with something like java Main -env MESSAGE=whateverIPutHere and it should print out whateverIPutHere.
Is it possible?
You can use the input arguments:
public static void main(String[] args) {
System.out.println(args[0]);
}
And then call it like this: java Main whateverIPutHere
Simple as that! args is an array containing all the arguments that you pass in the command line.