Question

Is there a way to add a method to System.out called printlnx that would prefix output with a string?

So, if I called :

System.out.printlnx("This is a test");

That it would print that with a prefix (specified by me) :

-prefix-->This is a test

NOTE: My intention is to mark all output from a console program so that its output appears distinct from a secondary console program that I run afterwards.

Answer 1

No. System.out is actually an object of type PrintStream. You can’t retrospectively add arbitrary methods to a particular object.

But you can very easily write one that lives in your own namespace:

public final class utils {
    public static void printlnx(String str) {
        System.out.println("-prefix-->" + str);
    }
}

Then elsewhere:

...

utils.printlnx("This is a test");