public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof PlumNeedle)) {
            return false;   
        }
        if (!super.equals(obj)) {
            return false;
        }
        return true;
    }

    /**
     * Returns a hash code for this instance.
     * 
     * @return A hash code.
     */
    public int hashCode() {
        return super.hashCode();
    }

    /**
     * Returns a clone of this needle.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException if the <code>PlumNeedle</code> 
     *     cannot be cloned (in theory, this should not happen).
     */
    public Object clone() throws CloneNotSupportedException {
        return super.clone();