Commons Lang、StandardToStringStyle#setFieldSeparatorAtEnd

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

public class C2009080400 {
    public static void main(String[] args) {
        StandardToStringStyle x = new StandardToStringStyle();
        System.out.println(x.isFieldSeparatorAtEnd());

        x.setFieldSeparatorAtEnd(true);
        System.out.println(x.isFieldSeparatorAtEnd());
    }
}

で、

false
true