Commons Lang、StandardToStringStyle#setFieldSeparatorAtStart

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

public class C2009080500 {
    public static void main(String[] args) {
        StandardToStringStyle x = new StandardToStringStyle();
        System.out.println(x.isFieldSeparatorAtStart());

        x.setFieldSeparatorAtStart(true);
        System.out.println(x.isFieldSeparatorAtStart());
    }
}

で、

false
true