@Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final VersionString other = (VersionString) obj;
        if (this.version != other.version && (this.version == null || !this.version.equals(other.version))) {
            return false;
        }
        return true;
    }