MXJ special charactor??

hello,

I found one big problem when i use below code for URLEncoding.
URLEncoder.encode(str, "UTF-8");

with farther more checking some example,
I found below mxj code working strange.

public class testEncoder extends MaxObject {
    public testEncoder() {
        declareIO(1, 1);
        createInfoOutlet(false);
    }

    public void bang() {
        post("%3A");
    }
}

when i send bang to this mxj object, i found folloing letters in max window.

-0X1.FE844199EA88P+0

does anybody has an idea about this??

thanks in advance.

best