{"id":671224,"date":"2026-01-07T13:06:49","date_gmt":"2026-01-07T12:06:49","guid":{"rendered":"https:\/\/blog.jetbrains.com\/?post_type=kotlin&p=671224"},"modified":"2026-01-13T10:47:27","modified_gmt":"2026-01-13T09:47:27","slug":"evaluating-kotlin-in-real-projects","status":"publish","type":"kotlin","link":"https:\/\/blog.jetbrains.com\/ko\/kotlin\/2026\/01\/evaluating-kotlin-in-real-projects\/","title":{"rendered":"\uc2e4\uc81c \ud504\ub85c\uc81d\ud2b8\uc5d0\uc11c Kotlin \ud3c9\uac00\ud558\uae30"},"content":{"rendered":"

\uc120\uc784 \uc18c\ud504\ud2b8\uc6e8\uc5b4 \uc5d4\uc9c0\ub2c8\uc5b4\uc774\uc790 JetBrains \uacf5\uc778 Kotlin \ud2b8\ub808\uc774\ub108\ub85c \ud65c\ub3d9 \uc911\uc778 Urs Peter<\/a>\uac00 \uae30\uace0\ud55c \uae00\uc785\ub2c8\ub2e4. Urs\ub294 \ub354 \uccb4\uacc4\uc801\uc778 \ubc29\ubc95\uc73c\ub85c Kotlin \uc5ed\ub7c9\uc744 \ub192\uc774\uace0 \uc2f6\uc740 \ub3c5\uc790\ub97c \ub300\uc0c1\uc73c\ub85c Xebia Academy\uc5d0\uc11c Kotlin \uc5ed\ub7c9 \uac15\ud654 \ud504\ub85c\uadf8\ub7a8<\/a>\ub3c4 \uc6b4\uc601\ud558\uace0 \uc788\uc2b5\ub2c8\ub2e4.<\/em><\/p>\n

\uc774 \uae00\uc740 <\/em>Java \uae30\ubc18 \ud658\uacbd\uc5d0\uc11c Kotlin\uc744 \uc131\uacf5\uc801\uc73c\ub85c \ub3c4\uc785\ud558\uae30 \uc704\ud55c \uc644\ubcbd \uac00\uc774\ub4dc<\/em><\/strong>\ub77c\ub294 \uc81c\ubaa9\uc758 \uc2dc\ub9ac\uc988 \uc911 \ub450 \ubc88\uc9f8 \uae00\uc785\ub2c8\ub2e4. \uc774 \uc2dc\ub9ac\uc988\ub294 \ud55c \uac1c\ubc1c\uc790\uc758 \ud638\uae30\uc2ec\uc5d0\uc11c \uc2dc\uc791\ud558\uc5ec \ud68c\uc0ac \uc804\uccb4\uc758 \ubcc0\ud654\ub85c \uc774\uc5b4\uc9c0\ub294 \uacfc\uc815\uc744 \ud1b5\ud574 \uc2e4\uc81c \ud300 \ub0b4\uc5d0\uc11c Kotlin \ub3c4\uc785\uc774 \uc5b4\ub5bb\uac8c \uc810\uc9c4\uc801\uc73c\ub85c \ud655\ub300\ub418\ub294\uc9c0 \ubcf4\uc5ec\uc90d\ub2c8\ub2e4.<\/em><\/p>\n

\uc774 \uc2dc\ub9ac\uc988\uc758 \uc804\uccb4 \uae00:<\/strong><\/p>\n

    \n
  1. Java \uac1c\ubc1c\uc790\ub97c \uc704\ud55c Kotlin \uc2dc\uc791\ud558\uae30<\/a><\/li>\n
  2. \uc2e4\uc81c \ud504\ub85c\uc81d\ud2b8\uc5d0\uc11c Kotlin \ud3c9\uac00\ud558\uae30<\/a><\/li>\n
  3. \ud68c\uc0ac\uc5d0 Kotlin \ub3c4\uc785 \ud655\uc7a5\ud558\uae30<\/a><\/li>\n
  4. Kotlin \ub3c4\uc785\uc5d0 \ub300\ud55c \uc758\uc0ac\uacb0\uc815\uad8c\uc790\uc758 \ub3d9\uc758 \uc774\ub04c\uc5b4\ub0b4\uae30<\/a><\/li>\n
  5. \uc870\uc9c1 \uc804\ubc18\uc73c\ub85c Kotlin \ub3c4\uc785 \ud655\uc7a5\ud558\uae30<\/a><\/li>\n<\/ol>\n
    \n

    \ud3c9\uac00 \ub2e8\uacc4: Kotlin \ud655\uc7a5 \uc751\uc6a9<\/strong><\/h2>\n

    \ud14c\uc2a4\ud2b8 \ub2e8\uacc4\uc5d0\uc11c Kotlin\uc744 \uc0ac\uc6a9\ud558\ub294 \ubc29\ubc95\uc744 \uc775\ud78c \ud6c4\uc5d0\ub294 \ub354 \uc2e4\uc9c8\uc801\uc778 \ud3c9\uac00\ub97c \uc2dc\uc791\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc5ec\uae30\uc5d0\ub294 \ud06c\uac8c \ub450 \uac00\uc9c0 \uc811\uadfc \ubc29\uc2dd\uc774 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n

      \n
    1. Kotlin\uc73c\ub85c \uc0c8\ub85c\uc6b4 \ub9c8\uc774\ud06c\ub85c\uc11c\ube44\uc2a4\/\uc560\ud50c\ub9ac\ucf00\uc774\uc158 \uad6c\ucd95<\/a><\/li>\n
    2. \uae30\uc874 Java \uc560\ud50c\ub9ac\ucf00\uc774\uc158 \ud655\uc7a5\/\ubcc0\ud658<\/a><\/li>\n<\/ol>\n

      1. Kotlin\uc73c\ub85c \uc0c8\ub85c\uc6b4 \ub9c8\uc774\ud06c\ub85c\uc11c\ube44\uc2a4\/\uc560\ud50c\ub9ac\ucf00\uc774\uc158 \uad6c\ucd95<\/strong><\/h3>\n

      \uc0c8\ub85c\uc6b4 \uc560\ud50c\ub9ac\ucf00\uc774\uc158\uc774\ub098 \ub9c8\uc774\ud06c\ub85c\uc11c\ube44\uc2a4\ub97c \ucc98\uc74c\ubd80\ud130 \uac1c\ubc1c\ud558\uba74 \uae30\uc874 \ucf54\ub4dc\uc758 \uc81c\uc57d \uc5c6\uc774 Kotlin\uc758 \ubaa8\ub4e0 \uae30\ub2a5\uc744 \ucda9\ubd84\ud788 \uc774\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\ub7ec\ud55c \uc811\uadfc \ubc29\uc2dd\uc740 \uc885\uc885 \uac00\uc7a5 \uc88b\uc740 \ud559\uc2b5 \uacbd\ud5d8\uc744 \uc81c\uacf5\ud558\uba70 Kotlin\uc758 \uc7a5\uc810\uc744 \uac00\uc7a5 \ubd84\uba85\ud558\uac8c \ubcf4\uc5ec\uc90d\ub2c8\ub2e4.<\/p>\n

      \n
      \n

      \uc804\ubb38\uac00 \ud301<\/strong>: \uc774 \ub2e8\uacc4\uc5d0\uc11c\ub294 \uc804\ubb38\uac00\uc758 \ub3c4\uc6c0\uc744 \uad6c\ud558\uc138\uc694. \ubb3c\ub860 \uac1c\ubc1c\uc790\ub85c\uc11c \uc790\uc2e0\uc758 \ub2a5\ub825\uc5d0 \ub2f9\uc5f0\ud788 \uc790\uc2e0\uc774 \uc788\uaca0\uc9c0\ub9cc, \ucd08\uae30 \uc2e4\uc218(\uc608: Java \uc2a4\ud0c0\uc77c\uc758 Kotlin \ucf54\ub4dc\ub97c \uc791\uc131\ud558\uac70\ub098 \uae30\ubcf8 Kotlin \ub77c\uc774\ube0c\ub7ec\ub9ac\ub97c \uc0ac\uc6a9\ud558\uc9c0 \uc54a\uc74c)\ub97c \ud53c\ud558\uba74 \uc218\uac1c\uc6d4\uc758 \uae30\uc220 \ubd80\ucc44\ub97c \uc904\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<\/div>\n

      \n
      \"\"<\/figure>\n<\/div>\n<\/div>\n

      Java \ubc30\uacbd\uc744 \uac00\uc9c4 \uac1c\ubc1c\uc790\ub77c\uba74 Kotlin\uc744 \uc0ac\uc6a9\ud560 \ub54c \ud53c\ud574\uc57c \ud560 \uba87 \uac00\uc9c0 \uc77c\ubc18\uc801\uc778 \ud568\uc815\uc744 \uc18c\uac1c\ud569\ub2c8\ub2e4.<\/p>\n

      \ud568\uc815: Java\uc5d0\uc11c \uc0ac\uc6a9\ud55c \uac83\uacfc \ub2e4\ub978 \ud504\ub808\uc784\uc6cc\ud06c \uc120\ud0dd<\/em><\/p>\n

      \ud301: \uae30\uc874 \ud504\ub808\uc784\uc6cc\ud06c\ub97c \uace0\uc218\ud558\uc138\uc694<\/strong>.<\/p>\n

      Java\uc5d0\uc11c Spring Boot\ub97c \uc0ac\uc6a9\ud558\uace0 \uc788\ub2e4\uba74 Kotlin\uc5d0\uc11c\ub3c4 \uacc4\uc18d \uc0ac\uc6a9\ud558\uc138\uc694. Spring Boot\ub294 Kotlin\uc744 \ucd5c\uace0 \uc218\uc900\uc73c\ub85c \uc9c0\uc6d0\ud558\ubbc0\ub85c \ub2e4\ub978 \ud504\ub808\uc784\uc6cc\ud06c\ub85c \uc804\ud658\ud558\uc5ec \uc5bb\uc744 \uc218 \uc788\ub294 \ucd94\uac00\uc801 \uc774\uc810\uc740 \uc5c6\uc2b5\ub2c8\ub2e4. \uac8c\ub2e4\uac00 \uc0c8\ub85c\uc6b4 \uc5b8\uc5b4\ub97c \ubc30\uc6cc\uc57c \ud560 \ubfd0\ub9cc \uc544\ub2c8\ub77c, \uc0c8\ub85c\uc6b4 \ud504\ub808\uc784\uc6cc\ud06c\ub3c4 \ucd94\uac00\ub85c \uc775\ud600\uc57c \ud558\ubbc0\ub85c \ubcf5\uc7a1\uc131\ub9cc \uac00\uc911\uc2dc\ud0ac \ubfd0 \uc544\ubb34\ub7f0 \uc774\uc810\ub3c4 \uc5c6\uc2b5\ub2c8\ub2e4.<\/p>\n

      \uc911\uc694 \ucc38\uace0 \uc0ac\ud56d<\/strong>: Spring\uc740 Kotlin\uc758 ‘\uc124\uacc4\uc5d0 \ub530\ub978 \uc0c1\uc18d’ \uc6d0\uce59\uacfc \ucda9\ub3cc\ud569\ub2c8\ub2e4. \uc774 \uc6d0\uce59\uc5d0 \ub530\ub77c \ud074\ub798\uc2a4\ub97c \ud655\uc7a5\ud558\ub824\uba74 \ud074\ub798\uc2a4\ub97c \uba85\uc2dc\uc801\uc73c\ub85c open\uc73c\ub85c \ud45c\uc2dc\ud574\uc57c \ud569\ub2c8\ub2e4.<\/p>\n

      \ubaa8\ub4e0 Spring \uad00\ub828 \ud074\ub798\uc2a4(@Configuration<\/code> \ub4f1)\uc5d0 open \ud0a4\uc6cc\ub4dc\ub97c \ucd94\uac00\ud558\uc9c0 \uc54a\uc73c\ub824\uba74 \ube4c\ub4dc \ud50c\ub7ec\uadf8\uc778(https:\/\/kotlinlang.org\/docs\/all-open-plugin.html#spring-support<\/a>)\uc744 \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc798 \uc54c\ub824\uc9c4 \uc628\ub77c\uc778 \ub3c4\uad6c\uc778 Spring Initializr<\/a>\uc744 \uc0ac\uc6a9\ud558\uc5ec Spring \ud504\ub85c\uc81d\ud2b8\ub97c \uc0dd\uc131\ud558\uba74 \uc774 \ube4c\ub4dc \ud50c\ub7ec\uadf8\uc778\uc774 \ubbf8\ub9ac \uad6c\uc131\ub418\uc5b4 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n

      \ud568\uc815: Kotlin \ud45c\uc900 \ub77c\uc774\ube0c\ub7ec\ub9ac \ub300\uc2e0 \uacf5\ud1b5 Java API\ub97c \uc0ac\uc6a9\ud558\uc5ec Java \uc2a4\ud0c0\uc77c\ub85c Kotlin \ucf54\ub4dc \uc791\uc131<\/em><\/p>\n

      \uc774\ub7ec\ud55c \ud568\uc815\uc740 \ub108\ubb34 \ub9ce\uc73c\ubbc0\ub85c \uba87 \uac00\uc9c0 \uac00\uc7a5 \ud754\ud55c \ud568\uc815\uc5d0 \ub300\ud574 \uc0b4\ud3b4\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n

      \ud568\uc815 1: Kotlin \uceec\ub809\uc158 \ub300\uc2e0 Java \uc2a4\ud2b8\ub9bc \uc0ac\uc6a9<\/em><\/h4>\n

      \ud301: \ud56d\uc0c1 Kotlin \uceec\ub809\uc158\uc744 \uc0ac\uc6a9\ud558\uc138\uc694.<\/strong><\/p>\n

      Kotlin \uceec\ub809\uc158\uc740 Java \uceec\ub809\uc158\uacfc \uc644\ubcbd\ud558\uac8c \uc0c1\ud638 \uc6b4\uc6a9 \uac00\ub2a5\ud558\uba70 \uac04\uacb0\ud558\uace0 \uae30\ub2a5\uc774 \ud48d\ubd80\ud55c \uace0\ucc28 \ud568\uc218\ub97c \uc81c\uacf5\ud558\ubbc0\ub85c Java \uc2a4\ud2b8\ub9bc\uc774 \ud544\uc694 \uc5c6\uc2b5\ub2c8\ub2e4.<\/p>\n

      \ub2e4\uc74c\uc740 \uc81c\ud488 \uce74\ud14c\uace0\ub9ac\ubcc4\ub85c \uadf8\ub8f9\ud654\ub41c \ub9e4\ucd9c\uc774 \uac00\uc7a5 \ub192\uc740(\uac00\uaca9 * \ud310\ub9e4\ub7c9) \uc0c1\uc704 3\uac1c \uc81c\ud488\uc744 \uc120\ud0dd\ud558\ub3c4\ub85d \uc124\uacc4\ub41c \uc608\uc785\ub2c8\ub2e4.<\/p>\n

      Java<\/strong><\/p>\n

      record Product(String name, String category, double price, int sold){}\n\nList products = List.of(\n           new Product(\"Lollipop\", \"sweets\", 1.2, 321),\n           new Product(\"Broccoli\", \"vegetable\", 1.8, 5);\n\nMap<String, List> top3RevenueByCategory =\n       products.stream()\n          .collect(Collectors.groupingBy(\n                Product::category,\n                Collectors.collectingAndThen(\n                    Collectors.toList(),\n                    list -> list.stream()\n                              .sorted(Comparator.comparingDouble(\n                                  (Product p) -> p.price() * p.sold())\n                                   .reversed())\n                                   .limit(3)\n                                   .toList()\n                       \t\t)\n          )\n);<\/pre>\n
      Kotlin<\/strong><\/p>\n
      val top3RevenueByCategory: Map<String, List> =\n   products.groupBy { it.category }\n       .mapValues { (_, list) ->\n           list.sortedByDescending { it.price * it.sold }.take(3)\n       }<\/pre>\n
      Kotlin\uc740 Java\uc640 \uc0c1\ud638 \uc6b4\uc6a9\uc774 \uac00\ub2a5\ud558\uae30 \ub54c\ubb38\uc5d0 \uae30\ubcf8 Kotlin\uacfc \ub9c8\ucc2c\uac00\uc9c0\ub85c Java \ud074\ub798\uc2a4\uc640 \ub808\ucf54\ub4dc\ub97c \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ud558\uc9c0\ub9cc Kotlin(\ub370\uc774\ud130) \ud074\ub798\uc2a4\ub97c \ub300\uc2e0 \uc0ac\uc6a9\ud560 \uc218\ub3c4 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
      \ud568\uc815 2: Java\uc758 Optional\uc744 \uacc4\uc18d\ud574\uc11c \uc0ac\uc6a9<\/em><\/h4>\n
      \ud301: Null \uac00\ub2a5 \ud0c0\uc785\uc744 \ud65c\uc6a9\ud558\uc138\uc694<\/strong>.<\/p>\n
      Java \uac1c\ubc1c\uc790\uac00 Kotlin\uc73c\ub85c \uc804\ud658\ud558\ub294 \ud575\uc2ec\uc801\uc778 \uc774\uc720 \uc911 \ud558\ub098\ub294 Kotlin\uc758 \uae30\ubcf8\uc801\uc778 null \uac12 \uac00\ub2a5\uc131 \uc9c0\uc6d0\uc73c\ub85c, NullPointerException\uc744 \uc644\uc804\ud788 \ubc29\uc9c0\ud560 \uc218 \uc788\ub2e4\ub294 \uac83\uc785\ub2c8\ub2e4. \ub530\ub77c\uc11c null \uac00\ub2a5 \ud0c0\uc785\ub9cc \uc0ac\uc6a9\ud558\uace0 Optional\uc740 \ud53c\ud558\uc138\uc694. \uc778\ud130\ud398\uc774\uc2a4\uc5d0 Optional\uc774 \uc5ec\uc804\ud788 \ud3ec\ud568\ub418\uc5b4 \uc788\ub098\uc694? \ub2e4\uc74c \ucf54\ub4dc\uc5d0\uc11c \ubcfc \uc218 \uc788\ub4ef\uc774 \uc774\ub97c null \uac00\ub2a5 \ud0c0\uc785\uc73c\ub85c \ubcc0\ud658\ud558\uba74 \uc27d\uac8c \uc81c\uac70\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
      Kotlin<\/strong><\/p>\n
      \/\/Let\u2019s assume this repository is hard to change, because it\u2019s a library you depend on\nclass OrderRepository {\n      \/\/it returns Optional, but we want nullable types\n      fun getOrderBy(id: Long): Optional = \u2026\n}\n\n\/\/Simply add an extension method and apply the orElse(null) trick\nfun OrderRepository.getOrderByOrNull(id: Long): Order? = \n                                    getOrderBy(id).orElse(null)\n\n\/\/Now enjoy the safety and ease of use of nullable types:\n\n\/\/Past:\n val g = repository.getOrderBy(12).flatMap { product ->\n     product.goody.map { it.name }\n}.orElse(\"No goody found\")\n\n\/\/Future:\n val g = repository.getOrderByOrNull(12)?.goody?.name ?: \"No goody found\"<\/pre>\n
      \ud568\uc815 3: \uc815\uc801 \ub798\ud37c\ub97c \uacc4\uc18d\ud574\uc11c \uc0ac\uc6a9<\/em><\/h4>\n
      \ud301: \ud655\uc7a5 \uba54\uc11c\ub4dc\ub97c \ud65c\uc6a9\ud558\uc138\uc694<\/strong>.<\/p>\n
      \ud655\uc7a5 \uba54\uc11c\ub4dc\ub294 \ub9ce\uc740 \uc774\uc810\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4.<\/p>\n