runtime/src/main/java/org/echocat/jomon/runtime/StringUtils.java
public static void addElement(@Nonnull StringBuilder buf, @Nonnull String separator, @Nonnull String element) {
        if (buf.length() > 0) {
            buf.append(separator);
        }
        buf.append(element);
    }
public static void addElement(@Nonnull StringBuilder buf, @Nonnull String separator, @Nonnull String element) {
        if (buf.length() > 0) {
            buf.append(separator);
        }
        buf.append(element);
    }
Appends the separator string, if <code>{@link StringBuilder#length() buf.lenght()} &gt; 0</code> and then appends the element.