How to get carriage return without line feed effect in Eclipse console?

It finally seems to be fixed in Mars!

Version: Mars Release (4.5.0)
Build id: 20150621-1200
Used Java: jre1.8.0_60

Your code

public class Main {

    public static void main(String[] args) {
        System.out.print("something\r");
        System.out.print(" any\r");
    }
}

Output

 anything

The bug is fixed by now (Eclipse 2020-03). Just go to

Window ➺ Preferences ➺ Run/Debug ➺ Console

and make sure that both checkboxes

Interpret ASCII control characters

and

Interpret Carriage Return (\r) as control character

are enabled.

As Nishant already pointed out in the comments, you've found a bug here.

This bug initially was reported in 2004 (>9 years ago!?!!) and this bug seems not to be fixed very soon (or ever). I tested it on several Eclipse version, even on Eclipse Juno SR2, and the bug is still there.