\u30af\u30e9\u30a6\u30c9\u30bd\u30ea\u30e5\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u90e8\u306e\u4eca\u91ce\u3067\u3059\uff01<\/p>\n
\u300cAndroid\u30a2\u30d7\u30ea\u3063\u3066Java\u3067\u4f5c\u308c\u3061\u3083\u3046\u304b\u3089Java\u3067\u4f5c\u308d\u3046\u300d<\/p>\n
\u300cKotlin\u3063\u3066Android\u30a2\u30d7\u30ea\u306b\u3057\u304b\u4f7f\u7528\u3067\u304d\u306a\u3055\u305d\u3046\u300d<\/p>\n
\u300c \u3042\u30fc\u8a00\u8a9e\u5b66\u7fd2\u306e\u30cf\u30fc\u30c9\u30eb\u9ad8\u305d\u3046\u306a\u30a4\u30e1\u30fc\u30b8\u300d<\/p>\n
\u975e\u5e38\u306b\u3082\u3063\u305f\u3044\u306a\u3044\uff01<\/p>\n
\u3068\u3044\u3046\u304a\u8a71\u3092\u4eca\u56de\u306f\u3055\u305b\u3066\u3044\u305f\u3060\u304d\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n
Kotlin\u3001\u975e\u5e38\u306b\u4fbf\u5229\u306a\u8a00\u8a9e\u306a\u3093\u3067\u3059\u3002<\/p>\n
\u4e00\u5ea6\u66f8\u3044\u305f\u3089\u75c5\u307f\u3064\u304d\u9593\u9055\u3044\u306a\u3057\u3067\u3059\u3002<\/p>\n
\u4eca\u56de\u306fAndroid\u30a2\u30d7\u30ea\u958b\u767a\u3067Kotlin\u3092\u4f7f\u3063\u305f\u6642\u306e\u9b45\u529b\u306b\u3064\u3044\u3066\u304a\u4f1d\u3048\u3057\u3066\u3044\u304d\u307e\u3059\uff01<\/p>\n
<\/p>\n
Kotlin\u306fJetBrains\u793e\u306b\u3088\u308a2011\u5e74\u306b\u516c\u958b\u3055\u308c\u307e\u3057\u305f\u3002<\/p>\n
Google\u306f2017\u5e74\u306bKotlin\u3092Android\u958b\u767a\u63a8\u5968\u8a00\u8a9e\u306b\u8a8d\u5b9a\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n
Android \u30a2\u30d7\u30ea\u3060\u3051\u3067\u306a\u304f\u3001iOS\u30a2\u30d7\u30ea\u3001Web\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u958b\u767a\u3082\u53ef\u80fd\u306a\u8a00\u8a9e\u3067\u3059\u3002<\/p>\n
\u30b3\u30fc\u30c9\u306b\u30bb\u30df\u30b3\u30ed\u30f3\u306f\u4e0d\u8981\u3067\u3054\u3056\u3044\u307e\u3059\u3002<\/p>\n
\u5730\u5473\u306b\u4fbf\u5229\u306a\u3093\u3067\u3059\u3002<\/p>\n
\u4f8b\u3048\u3070\u3001<\/p>\n
Java<\/p>\n
String str = \"hello\";<\/pre>\nKotlin<\/p>\n
var str: String = \"hello\"<\/pre>\n\u30bb\u30df\u30b3\u30ed\u30f3\u3088\u3055\u3089\u3070\uff01<\/p>\n
\u30c7\u30fc\u30bf\u30af\u30e9\u30b9\u3092\u4f5c\u6210\u3059\u308b\u3068\u304d\u306b\u77ed\u3044\u30b3\u30fc\u30c9\u3067\u66f8\u3051\u308b<\/h2>\n
\u307e\u305a\u306fJava\u306e\u30b3\u30fc\u30c9\u304b\u3089\u3002<\/p>\n
Java<\/p>\n
public class User {\n private final String name;\n private final int age;\n\n public User(String name, int age) {\n this.name = name;\n this.age = age;\n }\n public String getName() { return name; }\n public int getAge() { return age; }\n @Override public boolean equals(Object o){ \/* \u7565 *\/ }\n @Override public int hashCode(){ \/* \u7565 *\/ }\n @Override public String toString(){ \/* \u7565 *\/ }\n}\n<\/pre>\n\u3053\u306e\u3088\u3046\u306b\u3001equals\u30fbhashCode\u30fbtoString\u306e\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u304c\u5fc5\u8981\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
\u7d9a\u3044\u3066Kotlin\u3067\u3059\u3002<\/p>\n
data class User(val name: String, val age: Int)<\/pre>\n\u3053\u306e\u4e00\u6587\u3060\u3051\u3067getter\u30fbequals\u30fbhashCode\u30fbtoString \u304c\u81ea\u52d5\u751f\u6210\u3067\u304d\u3061\u3083\u3044\u307e\u3059\u3002<\/p>\n
Null\u6642\u3082\u5b89\u5fc3<\/h2>\n
Kotlin \u306f\u578b\u30b7\u30b9\u30c6\u30e0\u306b\u300cNullable \u578b\u300d\u3068\u300cNon-null \u578b\u300d\u3092\u7d44\u307f\u8fbc\u307f\u3001\u30b3\u30f3\u30d1\u30a4\u30eb\u6642\u306b\u30cc\u30eb\u53c2\u7167\u3092\u9632\u6b62\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n
Java<\/p>\n
\/\/ Java: NPE \u306e\u5371\u967a\u3042\u308a\nString s = possiblyNull();\nint len = s.length(); \/\/ NPE \u306e\u53ef\u80fd\u6027<\/pre>\nKotlin<\/p>\n
\/\/ Kotlin: \u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc\uff0f\u5b89\u5168\u547c\u3073\u51fa\u3057\nval s: String? = possiblyNull()\nval len = s?.length ?: 0 \/\/ null \u306e\u5834\u5408\u306f 0 \u3092\u8fd4\u3059\n<\/pre>\n\u3053\u306e\u3088\u3046\u306bnull\u6642\u306e\u30ea\u30b9\u30af\u3092\u6e1b\u3089\u3059\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n
Swift\u306b\u66f8\u304d\u65b9\u304c\u4f3c\u3066\u3044\u308b<\/h2>\n
\u62e1\u5f35\u6a5f\u80fd\u5b9f\u88c5\u6642\u306eSwift\u3068\u3082\u6bd4\u8f03\u3092\u3057\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
Swift<\/p>\n
let message = \"Hello, Swift\" \/\/ String \u3068\u63a8\u8ad6\nvar count = 0 \/\/ Int \u3068\u63a8\u8ad6\n\nextension String {\n func isEmail() -> Bool {\n \/\/ \u6b63\u898f\u8868\u73fe\u3067\u30c1\u30a7\u30c3\u30af\u2026\n return self.contains(\"@\")\n }\n}<\/pre>\nKotlin<\/p>\n
val message = \"Hello, Kotlin\" \/\/ String \u3068\u63a8\u8ad6\nvar count = 0 \/\/ Int \u3068\u63a8\u8ad6\n\nfun String.isEmail(): Boolean {\n \/\/ \u6b63\u898f\u8868\u73fe\u3067\u30c1\u30a7\u30c3\u30af\u2026\n return contains(\"@\")\n}<\/pre>\n\u578b\u5b9a\u7fa9\u3068\u62e1\u5f35\u6a5f\u80fd\u3092\u7d39\u4ecb\u3057\u307e\u3057\u305f\u304c\u3001<\/p>\n
Swift \u3082 Kotlin \u3082\u3001\u5909\u6570\u5ba3\u8a00\u6642\u306b\u578b\u3092\u307b\u3068\u3093\u3069\u660e\u793a\u3059\u308b\u5fc5\u8981\u304c\u306a\u304f\u3001\u53f3\u8fba\u304b\u3089\u578b\u3092\u63a8\u8ad6\u3057\u307e\u3059\u3002<\/p>\n
\u65e2\u5b58\u30af\u30e9\u30b9\u306b\u30e1\u30bd\u30c3\u30c9\u3092\u300c\u8ffd\u52a0\u300d\u3067\u304d\u308b\u4ed5\u7d44\u307f\u3082\u5171\u901a\u3067\u3059\u3002<\/p>\n
iOS\u30a2\u30d7\u30ea\u958b\u767a\u3082\u53ef\u80fd\uff01<\/h2>\n
\u5148\u307b\u3069\u306e\u6587\u3092\u898b\u3066\u3001\u52d8\u306e\u92ed\u3044\u65b9\u306f\u6c17\u3065\u304f\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002<\/p>\n
Android\u30a2\u30d7\u30ea\u306e\u958b\u767a\u8a00\u8a9e\u306a\u306e\u306b\u3001iPhone\u30a2\u30d7\u30ea\u3082\u4f5c\u308c\u308b\u306e\u2026\uff1f<\/p>\n
\u4f5c\u308c\u308b\u3093\u3067\u3059\u3002<\/p>\n
JetBrains\u793e\u304c\u30ea\u30ea\u30fc\u30b9\u3057\u3066\u3044\u308bKotlin Multiplatform\u3092\u4f7f\u3063\u3066\u4f5c\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n