Commons Lang、StandardToStringStyle#setSizeStartText

import org.apache.commons.lang.builder.StandardToStringStyle;

public class C2009080800 {
    public static void main(String[] args) {
        StandardToStringStyle x = new StandardToStringStyle();
        System.out.println(x.getSizeStartText());

        x.setSizeStartText("[");
        System.out.println(x.getSizeStartText());
    }
}

で、

<size=
[