How to execute Java code within Java comments

31 / May / 2016 by Sandeep Gupta 2 comments

We all know Java comments are not visible to compiler and are not executable. But here we will see how a comment can be executed. To execute any comment we need to append a unicode as prefix to that comment and thats it. Now when you will run the code then this comment line will be executed.

public class CommentTest {
	public static void main(String[] args)
	{
		// Following line will be executed and will produce output.
		// \u000d System.out.println("This is the output generated from commented line");
	}
}
Output:
This is the output generated from commented line

Why this is happening? Following is the explanation taken from  Java Language Specification – Section 3.3

The Java programming language specifies a standard way of transforming a program written in Unicode into ASCII that changes a program into a form that can be processed by ASCII-based tools. The transformation involves converting any Unicode escapes in the source text of the program to ASCII by adding an extra u – for example, \uxxxxbecomes \uuxxxx – while simultaneously converting non-ASCII characters in the source text to Unicode escapes containing a single u each.

FOUND THIS USEFUL? SHARE IT

comments (2)

  1. anjali

    Hi,
    Nice article about how to execute Java code within Java comments and easy to understand to java learners. Can yo explain about Is there a plan for Java 8 in Android?
    Thanks,
    Anjali,

    Reply

Leave a comment -