{"id":46017,"date":"2022-03-23T00:51:12","date_gmt":"2022-03-22T15:51:12","guid":{"rendered":"https:\/\/www.charlezz.com\/?p=46017"},"modified":"2022-03-23T01:58:51","modified_gmt":"2022-03-22T16:58:51","slug":"%ec%98%a4%ed%86%a0%eb%b0%95%ec%8b%b1-%eb%b0%8f-%ec%96%b8%eb%b0%95%ec%8b%b1-%ea%b7%b8%eb%a6%ac%ea%b3%a0-jvm%eb%82%b4-%ec%ba%90%ec%8b%9c%ec%97%90-%eb%8c%80%ed%95%98%ec%97%ac","status":"publish","type":"post","link":"https:\/\/charlezz.com\/?p=46017","title":{"rendered":"\uc624\ud1a0\ubc15\uc2f1 \ubc0f \uc5b8\ubc15\uc2f1 \uadf8\ub9ac\uace0 JVM\ub0b4 \uce90\uc2dc\uc5d0 \ub300\ud558\uc5ec"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Autoboxing vs Unboxing<\/h2>\n\n\n\n<p>\uc624\ud1a0\ubc15\uc2f1(Autoboxing)\uc740 Java \ucef4\ud30c\uc77c\ub7ec\uac00 \uc6d0\uc2dc \ud0c0\uc785(Primitive types)\uacfc \ud574\ub2f9 \uac1d\uccb4 \ub798\ud37c \ud074\ub798\uc2a4 \uac04\uc5d0 \uc218\ud589\ud558\ub294 \uc790\ub3d9 \ubcc0\ud658\uc744 \ub9d0\ud55c\ub2e4. \uc608\ub97c \ub4e4\uc5b4 int\ub97c Integer\ub85c, double\uc744 Double\ub85c \ubcc0\ud658\ud558\ub294 \uc2dd\uc774\ub2e4. \ubcc0\ud658\uc774 \ub2e4\ub978 \ubc29\ud5a5\uc73c\ub85c \uc9c4\ud589\ub418\ub294 \uacbd\uc6b0 \uc774\ub97c \uc5b8\ubc15\uc2f1(unboxing)\uc774\ub77c\uace0 \ud55c\ub2e4.<\/p>\n\n\n\n<p>\ub2e4\uc74c \uac04\ub2e8\ud55c \uc624\ud1a0\ubc15\uc2f1 \uc608\uc81c\ub97c \uc0b4\ud3b4\ubcf4\uc790.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Character ch = 'a';<\/code><\/pre>\n\n\n\n<p>&#8216;a&#8217;\uc758 \ud0c0\uc785\uc740 char\uc778\ub370 Character\uc5d0 \ub300\uc785\ud588\ub2e4. \uc774\ub807\uac8c \ud574\ub3c4 \ud638\ud658\uc774 \ub418\uba70 \uc774\uac83\uc774 \uc624\ud1a0\ubc15\uc2f1\uc774\ub2e4.<\/p>\n\n\n\n<p>\ub2e4\uc74c \uc608\uc81c\ucf54\ub4dc\ub97c \uc0b4\ud3b4\ubcf4\uc790.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>List&lt;Integer&gt; li = new ArrayList&lt;&gt;();\nfor (int i = 1; i &lt; 50; i += 2)\n    li.add(<strong>i<\/strong>);<\/code><\/pre>\n\n\n\n<p>int \uac12\uc744 Integer \uac1d\uccb4\uac00 \uc544\ub2cc \uae30\ubcf8 \uc720\ud615\uc73c\ub85c li\uc5d0 \ucd94\uac00\ud558\ub354\ub77c\ub3c4 \ucf54\ub4dc\uac00 \ucef4\ud30c\uc77c\ub41c\ub2e4. li\ub294 int \uac12 List\uac00 \uc544\ub2c8\ub77c Integer \uac1d\uccb4 List\uc774\uae30 \ub54c\ubb38\uc5d0 Java \ucef4\ud30c\uc77c\ub7ec\uac00 \ucef4\ud30c\uc77c \ud0c0\uc784 \uc624\ub958\ub97c \ubc1c\uc0dd\uc2dc\ud0a4\uc9c0 \uc54a\ub294\uc9c0 \uc758\ubb38\uc774 \uc0dd\uae38 \uc218 \uc788\ub2e4. \uadf8\ub7ec\ub098 \ucef4\ud30c\uc77c\ub7ec\ub294 i\uc5d0\uc11c Integer \uac1d\uccb4\ub97c \ub9cc\ub4e4\uace0 li\uc5d0 \uac1d\uccb4\ub97c \ucd94\uac00\ud558\uae30 \ub54c\ubb38\uc5d0 \uc624\ub958\uac00 \uc0dd\uae30\uc9c0\ub294 \uc54a\ub294\ub2e4. <\/p>\n\n\n\n<p>\ub530\ub77c\uc11c \ucef4\ud30c\uc77c\ub7ec\ub294 \ub7f0\ud0c0\uc784\uc5d0 \uc704 \ucf54\ub4dc\ub97c \ub2e4\uc74c \ucf54\ub4dc\ub85c \ubcc0\ud658\ud55c\ub2e4.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>List&lt;Integer&gt; li = new ArrayList&lt;&gt;();\nfor (int i = 1; i &lt; 50; i += 2)\n    li.add(<strong>Integer.valueOf(i)<\/strong>);<\/code><\/pre>\n\n\n\n<p>\uc704\uc758 \uc608\uc81c\ucc98\ub7fc \uc6d0\uc2dc\ud0c0\uc785\uc758 \uac12\uc744 \uc801\ub2f9\ud55c \ub798\ud37c \ud074\ub798\uc2a4\uc758 \ud0c0\uc785\uc73c\ub85c \ubcc0\uacbd\ud558\ub294 \uac83\uc744 <strong>\uc624\ud1a0\ubc15\uc2f1<\/strong>\uc774\ub77c\uace0 \ud55c\ub2e4.<\/p>\n\n\n\n<p>\ub610 \ub2e4\ub978 \uc608\uc81c\ucf54\ub4dc\ub97c \uc0b4\ud3b4\ubcf4\uc790.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public static int sumEven(List&lt;Integer&gt; li) {\n    int sum = 0;\n    for (Integer i: li)\n        if (i % 2 == 0)\n            sum += i;\n        return sum;\n}<\/code><\/pre>\n\n\n\n<p>&#8216;%&#8217; \uc5f0\uc0b0\uc790\ub294 \ubc0f &#8216;+=&#8217; \uc5f0\uc0b0\uc790\ub294 \uc77c\ubc18\uc801\uc73c\ub85c \uac1d\uccb4\uc5d0\ub294 \uc801\uc6a9\uc774 \uc548\ub418\uae30 \ub54c\ubb38\uc5d0 \ucef4\ud30c\uc77c\ub7ec\uac00 \uc5b4\ub5bb\uac8c \uc5d0\ub7ec\uc5c6\uc774 \uc774\ub7ec\ud55c \uc791\uc5c5\uc744 \uc218\ud589\ud558\ub294\uc9c0 \uad81\uae08\ud560 \uac83\uc774\ub2e4. \ucef4\ud30c\uc77c\ub7ec\ub294 \ub7f0\ud0c0\uc784\uc5d0 Integer\ub97c int\ub85c \ubcc0\ud658\ud558\uae30 \uc704\ud574 \ub2e4\uc74c\uacfc \uac19\uc774 intValue \uba54\uc11c\ub4dc\ub97c \ud638\ucd9c\b\ud55c\ub2e4.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public static int sumEven(List&lt;Integer&gt; li) {\n    int sum = 0;\n    for (Integer i : li)\n        if (i.intValue() % 2 == 0)\n            sum += i.intValue();\n        return sum;\n}<\/code><\/pre>\n\n\n\n<p>\ub798\ud37c \ud074\ub798\uc2a4 \ud0c0\uc785\uc758 \uac1d\uccb4\ub97c \uc6d0\uc2dc \ud0c0\uc785 \uac12\uc73c\ub85c \ubcc0\uacbd\ud558\ub294 \uac83\uc744 <strong>\uc5b8\ubc15\uc2f1<\/strong>\uc774\ub77c\uace0 \ud55c\ub2e4. <\/p>\n\n\n\n<p>\uc624\ud1a0\ubc15\uc2f1 \ubc0f \uc5b8\ubc15\uc2f1\uc744 \ud1b5\ud574 \uac1c\ubc1c\uc790\ub294 \ubcf4\ub2e4 \uae54\ub054\ud55c \ucf54\ub4dc\ub97c \uc791\uc131\ud560 \uc218 \uc788\uc73c\ubbc0\ub85c \uc77d\uae30 \uc27d\ub2e4. \ub2e4\uc74c\uc740 \uc624\ud1a0\ubc15\uc2f1 \ubc0f \uc5b8\ubc15\uc2f1\uc744 \uc704\ud574 Java \ucef4\ud30c\uc77c\ub7ec\uc5d0\uc11c \uc0ac\uc6a9\ud558\ub294 \uc6d0\uc2dc \ud0c0\uc785 \ubc0f \ud574\ub2f9 \ub798\ud37c \ud074\ub798\uc2a4\ub97c \ub098\uc5f4\ud55c\ub2e4.<\/p>\n\n\n\n<ul><li>boolean &lt;-&gt; Boolean<\/li><li>byte &lt;-&gt; Byte<\/li><li>char &lt;-&gt; Character<\/li><li>float &lt;-&gt; Float<\/li><li>int &lt;-&gt; Integer<\/li><li>long &lt;-&gt; Long<\/li><li>short &lt;-&gt; Short<\/li><li>double &lt;-&gt; Double<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">JVM \ub0b4\uc5d0 \uce90\uc2dc \ub41c \ubb38\uc790\uc5f4 \ubc0f \ubc15\uc2f1\ub41c \uc6d0\uc2dc\ud0c0\uc785 \uac1d\uccb4\ub4e4<\/h2>\n\n\n\n<p>JVM\ub0b4\uc5d0\uc11c\ub294 \ud558\ub098\uc758 \uac00\uc0c1 \uba38\uc2e0\uc5d0\uc11c \ub3d9\uc77c\ud55c \ubb38\uc790\uc5f4\uc744 \ucc98\ub9ac\ud558\ub294 \ucf54\ub4dc\uac00 \uc5ec\ub7ec \uac1c \uc788\ub2e4\uba74, \uae30\uc874\uc758 \ubb38\uc790\uc5f4\uc744 \uc7ac\uc0ac\uc6a9 \ud55c\ub2e4.<\/p>\n\n\n<pre class=\"kotlin-code\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\nfun main() {\n\tval str1 = &quot;Charles&quot;\n    val str2 = &quot;Charles&quot;\n    val str3 = StringBuilder(&quot;Charles&quot;).toString()\n    \n    println(str1 == str2) \/\/ true, \ub3d9\ub4f1\uc131 \ube44\uad50\n    println(str1 === str2) \/\/ true, \ub808\ud37c\ub7f0\uc2a4(\uba54\ubaa8\ub9ac \uc8fc\uc18c) \ube44\uad50\n    println(str2 === str3) \/\/ false, \uc0c8\ub85c\uc6b4 \uac1d\uccb4 \uc0dd\uc131 (\uc0c8\ub85c\uc6b4 \uba54\ubaa8\ub9ac \ud560\ub2f9)\n    println(str2 === str3.intern()) \/\/ true, JVM \ubb38\uc790\uc5f4 pool\uc5d0 \uc788\ub294 \uac1d\uccb4\ub97c \uac00\uc838\uc634\n}\n<\/pre>\n\n\n\n<p>Integer\uc640 Long\ucc98\ub7fc \ubc15\uc2a4\ud654\ud55c \uae30\ubcf8 \uc790\ub8cc\ud615\ub3c4 \uae30\ubcf8\uc801\uc73c\ub85c -128~127 \ubc94\uc704\ub97c \uce90\uc2dc\ud55c\ub2e4.<\/p>\n\n\n<pre class=\"kotlin-code\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\nfun main() {\n\tval i1: Int? = 1\n    val i2: Int? = 1\n    val i3: Int? = 1000\n    val i4: Int? = 1000\n  \n    println(i1==i2) \/\/ true, \uac12 \ube44\uad50\n    println(i1===i2) \/\/ true, \ub808\ud37c\ub7f0\uc2a4 \ube44\uad50\n    println(i3==i4) \/\/ true, \uac12 \ube44\uad50\n    println(i3===i4) \/\/ \uce90\uc2dc\ub418\uc9c0 \uc54a\ub294 \uac12\uc774\ubbc0\ub85c false\ub97c \ubc18\ud658, \ub808\ud37c\ub7f0\uc2a4 \ube44\uad50\n}\n<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\ucf54\ub8e8\ud2f4 \uc2a4\ucf54\ud504 \ub0b4\uc5d0\uc11c\ub294 \uce90\uc2dc\ub418\uc9c0 \uc54a\ub294\ub2e4.<\/h3>\n\n\n\n<p>\uc704\uc758 \uc608\uc81c \ucf54\ub4dc\ub97c \uac04\ub2e8\ud788 runBlocking \uc2a4\ucf54\ud504\ub85c \uac10\uc2f8\ubcf4\uc790.<\/p>\n\n\n<pre class=\"kotlin-code\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\nimport kotlinx.coroutines.*\n\nfun main() = runBlocking {\n    val str1 = &quot;Charles&quot;\n    val str2 = &quot;Charles&quot;\n    val str3 = StringBuilder(&quot;Charles&quot;).toString()\n    \n    println(str1 == str2) \/\/ true\n    println(str1 === str2) \/\/ true\n    println(str2 === str3) \/\/ false\n    println(str2 === str3.intern()) \/\/ true\n}\n<\/pre>\n\n\n\n<p>String \ubb38\uc790\uc5f4\uc758 \uacbd\uc6b0 \ucf54\ub8e8\ud2f4 \uc2a4\ucf54\ud504 \ub0b4\uc5d0\uc11c\ub3c4 \uae30\uc874 \uc608\uc81c\ucf54\ub4dc\uc640 \ub3d9\uc77c\ud55c \uacb0\uacfc\ub97c \ub098\ud0c0\ub0b8\ub2e4. \ud558\uc9c0\ub9cc \ub2e4\uc74c \ubc15\uc2f1\ub41c \uc6d0\uc2dc \ud0c0\uc785\uc758 \uce90\uc2f1 \uc608\uc81c \ucf54\ub4dc\ub97c \uc0b4\ud3b4\ubcf4\uc790.<\/p>\n\n\n<pre class=\"kotlin-code\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\nimport kotlinx.coroutines.*\n\nfun main() = runBlocking {\n    val i1: Int? = 1\n    val i2: Int? = 1\n    val i3: Int? = 1000\n    val i4: Int? = 1000\n  \n    println(i1==i2) \/\/ true\n    println(i1===i2) \/\/ false, \uce90\uc2f1\ub418\uc9c0 \uc54a\uc74c\n    println(i3==i4) \/\/ true\n    println(i3===i4) \/\/ false\n}\n<\/pre>\n\n\n\n<p>(i1 === i2) \uc758 \ube44\uad50\uac00 false\ub97c \ub9ac\ud134\ud558\ub294 \uac83\uc744 \ud655\uc778\ud560 \uc218 \uc788\ub2e4. \uc77c\ubc18\uc801\uc778 \ud568\uc218\uc5d0\uc11c \uc218\ud589\uc2dc \uce90\uc2dc\ub418\ub294 \uac83\uc744 \ud655\uc778\ud560 \uc218 \uc788\uc5c8\ub294\ub370, \ucf54\ub8e8\ud2f4 \uc2a4\ucf54\ud504\uc5d0\uc11c\ub294 \uc65c \uacb0\uacfc\uac00 \ub2ec\ub77c\uc84c\uc744\uae4c?<\/p>\n\n\n\n<p>\ud574\ub2f9 \ucf54\ub4dc\ub4e4\uc744 \ub514\ucef4\ud30c\uc77c \ud574\ubcf4\uc558\ub2e4.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" loading=\"lazy\" width=\"1024\" height=\"459\" src=\"https:\/\/www.charlezz.com\/wordpress\/wp-content\/uploads\/2022\/03\/www.charlezz.com-jvm-screenshot-1-1024x459.png\" alt=\"\" class=\"wp-image-46019\" srcset=\"https:\/\/charlezz.com\/wordpress\/wp-content\/uploads\/2022\/03\/www.charlezz.com-jvm-screenshot-1-1024x459.png 1024w, https:\/\/charlezz.com\/wordpress\/wp-content\/uploads\/2022\/03\/www.charlezz.com-jvm-screenshot-1-300x134.png 300w, https:\/\/charlezz.com\/wordpress\/wp-content\/uploads\/2022\/03\/www.charlezz.com-jvm-screenshot-1-768x344.png 768w, https:\/\/charlezz.com\/wordpress\/wp-content\/uploads\/2022\/03\/www.charlezz.com-jvm-screenshot-1-1536x688.png 1536w, https:\/\/charlezz.com\/wordpress\/wp-content\/uploads\/2022\/03\/www.charlezz.com-jvm-screenshot-1-2048x917.png 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>\ube68\uac04\uc0c9 \uc0c1\uc790\ub85c \ub9c8\ud0b9\ud574\ub454 \ubd80\ubd84\uc774 \ub208\uc5ec\uaca8 \ubcfc \ubd80\ubd84\uc774\ub2e4. \uc67c\ucabd\uc740 \ucef4\ud30c\uc77c \ub41c \uc774\ud6c4\uc5d0 JVM\ub0b4 \uce90\uc2dc\ub41c \uac12\uc744 \ucc38\uc870\ud558\uace0 \uc788\ub294\ub370, \uc624\ub978\ucabd\uc740 Boxing.boxInt(&#8230;) \ub97c \ucc38\uc870\ud558\uace0 \uc788\ub2e4. \uc774\ub807\uac8c \ub418\uba74 \ub0b4\ubd80\uc801\uc73c\ub85c \uac1d\uccb4\ub97c \uc0c8\ub85c \uc0dd\uc131\ud558\uac8c \ub418\uace0 \uc0c8\ub85c\uc6b4 \uba54\ubaa8\ub9ac\ub97c \ud560\ub2f9 \ubc1b\uc73c\ubbc0\ub85c \ub808\ud37c\ub7f0\uc2a4\uac00 \uac08\ub9ac\uac8c \ub41c\ub2e4.<\/p>\n\n\n\n<p>\ucf54\ub8e8\ud2f4 \uc2a4\ucf54\ud504\uc5d0\uc11c \ucef4\ud30c\uc77c\ub7ec\uc758 \ub3d9\uc791\uc774 \uc65c \ub2e4\ub978\uc9c0\ub294 \ubaa8\ub974\uaca0\ub2e4. \ud558\uc9c0\ub9cc \ubc15\uc2f1\ub41c \uae30\ubcf8 \uc790\ub8cc\ud615\uc774 \uce90\uc2dc \ub418\uc9c0 \uc54a\ub294 \uacbd\uc6b0\ub3c4 \uc788\ub2e4 \uc815\ub3c4\ub9cc \uc54c\uace0 \ub118\uc5b4\uac00\ub3c4\ub85d \ud558\uc790.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Autoboxing vs Unboxing \uc624\ud1a0\ubc15\uc2f1(Autoboxing)\uc740 Java \ucef4\ud30c\uc77c\ub7ec\uac00 \uc6d0\uc2dc \ud0c0\uc785(Primitive types)\uacfc \ud574\ub2f9 \uac1d\uccb4 \ub798\ud37c \ud074\ub798\uc2a4 \uac04\uc5d0 \uc218\ud589\ud558\ub294 \uc790\ub3d9 \ubcc0\ud658\uc744 \ub9d0\ud55c\ub2e4. \uc608\ub97c \ub4e4\uc5b4 int\ub97c Integer\ub85c, double\uc744 Double\ub85c \ubcc0\ud658\ud558\ub294 \uc2dd\uc774\ub2e4. \ubcc0\ud658\uc774 \ub2e4\ub978 \ubc29\ud5a5\uc73c\ub85c \uc9c4\ud589\ub418\ub294 \uacbd\uc6b0 \uc774\ub97c \uc5b8\ubc15\uc2f1(unboxing)\uc774\ub77c\uace0 \ud55c\ub2e4. \ub2e4\uc74c \uac04\ub2e8\ud55c \uc624\ud1a0\ubc15\uc2f1 \uc608\uc81c\ub97c \uc0b4\ud3b4\ubcf4\uc790. &#8216;a&#8217;\uc758 \ud0c0\uc785\uc740 char\uc778\ub370 Character\uc5d0 \ub300\uc785\ud588\ub2e4. \uc774\ub807\uac8c \ud574\ub3c4 \ud638\ud658\uc774 \ub418\uba70 \uc774\uac83\uc774 \uc624\ud1a0\ubc15\uc2f1\uc774\ub2e4. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"inline_featured_image":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0},"categories":[25,5],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/charlezz.com\/index.php?rest_route=\/wp\/v2\/posts\/46017"}],"collection":[{"href":"https:\/\/charlezz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/charlezz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/charlezz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/charlezz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=46017"}],"version-history":[{"count":3,"href":"https:\/\/charlezz.com\/index.php?rest_route=\/wp\/v2\/posts\/46017\/revisions"}],"predecessor-version":[{"id":46021,"href":"https:\/\/charlezz.com\/index.php?rest_route=\/wp\/v2\/posts\/46017\/revisions\/46021"}],"wp:attachment":[{"href":"https:\/\/charlezz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=46017"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/charlezz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=46017"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/charlezz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=46017"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}