class Ideone {
  public static void main(String[] args) {
    String groupName = null;  // nullデータのため、結合しない
    String companyName = "テスト会社";
    String busyo = "テスト部署";
    String yakusyoku = null ; // nullデータのため、結合しない
    String tantousya = "テスト太郎";
 
    String ketugo = concat(groupName, companyName, busyo, yakusyoku, tantousya);
    System.out.println(ketugo);
  }
 
  public static String concat(String ...args) {
  	StringBuffer buf = new StringBuffer();
    for (String arg : args) {
      if (arg != null) buf.append(arg);
    }
    return buf.toString();
  }
}

Y2xhc3MgSWRlb25lIHsKICBwdWJsaWMgc3RhdGljIHZvaWQgbWFpbihTdHJpbmdbXSBhcmdzKSB7CiAgICBTdHJpbmcgZ3JvdXBOYW1lID0gbnVsbDsgIC8vIG51bGzjg4fjg7zjgr/jga7jgZ/jgoHjgIHntZDlkIjjgZfjgarjgYQKICAgIFN0cmluZyBjb21wYW55TmFtZSA9ICLjg4bjgrnjg4jkvJrnpL4iOwogICAgU3RyaW5nIGJ1c3lvID0gIuODhuOCueODiOmDqOe9siI7CiAgICBTdHJpbmcgeWFrdXN5b2t1ID0gbnVsbCA7IC8vIG51bGzjg4fjg7zjgr/jga7jgZ/jgoHjgIHntZDlkIjjgZfjgarjgYQKICAgIFN0cmluZyB0YW50b3VzeWEgPSAi44OG44K544OI5aSq6YOOIjsKICAgIAogICAgU3RyaW5nIGtldHVnbyA9IGNvbmNhdChncm91cE5hbWUsIGNvbXBhbnlOYW1lLCBidXN5bywgeWFrdXN5b2t1LCB0YW50b3VzeWEpOwogICAgU3lzdGVtLm91dC5wcmludGxuKGtldHVnbyk7CiAgfQogIAogIHB1YmxpYyBzdGF0aWMgU3RyaW5nIGNvbmNhdChTdHJpbmcgLi4uYXJncykgewogIAlTdHJpbmdCdWZmZXIgYnVmID0gbmV3IFN0cmluZ0J1ZmZlcigpOwogICAgZm9yIChTdHJpbmcgYXJnIDogYXJncykgewogICAgICBpZiAoYXJnICE9IG51bGwpIGJ1Zi5hcHBlbmQoYXJnKTsKICAgIH0KICAgIHJldHVybiBidWYudG9TdHJpbmcoKTsKICB9Cn0=