the concat() method in java.lang.String won't succeed with a substring as an arg

[vbo 12/4/95]

The string returned from a substring() call cannot be successfully used as an argument
to the concat() call on another string. The following short program demonstrates the
problem.

---- Bug.java ----

class Bug {
    public static void main(String argv[]) {
        String s1 = new String("012345678901234567890..25...30...35");
        String s2 = new String("Numbers will be concatenated here: ");

        // it seems you can't concatenate a substring
        s2.concat(s1.substring(0, 21));
        System.out.println(s2);

        // here's a workaround
        s2 = s2 + s1.substring(0, 21);
        System.out.println(s2);
    }
}


---- output of above ----

(vbo) rootbeer other> javac Bug.java
0 errors
(vbo) rootbeer other> java Bug
Numbers will be concatenated here:
Numbers will be concatenated here: 012345678901234567890