{"id":777,"date":"2004-09-12T09:00:00","date_gmt":"2004-09-12T00:00:00","guid":{"rendered":"\/?p=777"},"modified":"2004-09-12T09:00:00","modified_gmt":"2004-09-12T00:00:00","slug":"java-performance-tips","status":"publish","type":"post","link":"https:\/\/www.hiro345.net\/blogs\/hiro345\/archives\/777.html","title":{"rendered":"Java Performance Tips"},"content":{"rendered":"

Java World \u3092\u30d1\u30e9\u30d1\u30e9\u3081\u304f\u3063\u3066\u3044\u305f\u3089\u8f09\u3063\u3066\u3044\u305f\u306e\u3067\u30e1\u30e2\u3002\u3061\u3087\u3063\u3068\u3057\u305f\u5de5\u592b\u3067\u901f\u304f\u306a\u308b\u307f\u305f\u3044\u3067\u3059\u3002\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u5229\u7528\u3068\u3044\u3046\u306e\u304c\u3061\u3087\u3063\u3068\u610f\u5916\u304b\u3082\u3002<\/p>\n

import java.util.Collections;
\nimport java.util.List;<\/p>\n

public class ListNcopy {
\n public static void main(String[] args) {
\n \/\/\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u7a7a\u30ea\u30b9\u30c8\u4f5c\u6210 … \u901f\u3044
\n List list = Collections.nCopies(10000, null);
\n \/\/\u3053\u306e\u307e\u307e\u3067\u306flist\u306f\u4e0d\u5909\u306a\u306e\u3067\u3001\u3053\u308c\u304b\u3089
\n \/\/\u53ef\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u7a7a\u30ea\u30b9\u30c8\u3092\u4f5c\u6210
\n List arrayList = new ArrayList();
\n arrayList.addAll(list);
\n \/\/List\u304b\u3089List\u3078\u306e\u30b3\u30d4\u30fc\u306b\u306f\u3001\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3092
\n \/\/\u5229\u7528\u3059\u308b\u3068\u901f\u3044
\n List copiedList = new ArrayList(arrayList);
\n \/\/\u914d\u5217\u3092List\u3078\u5909\u63db\u3059\u308b\u306b\u306f\u3001\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092
\n \/\/asList\u30e1\u30bd\u30c3\u30c9\u3067\u53d6\u5f97\u3057\u3066\u304b\u3089\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u5229\u7528
\n Integer[] iArray = new Integer[10000];
\n List iList = Arrays.asList(iArray);
\n List copiediList = new ArrayList(list);
\n }
\n}<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

Java World \u3092\u30d1\u30e9\u30d1\u30e9\u3081\u304f\u3063\u3066\u3044\u305f\u3089\u8f09\u3063\u3066\u3044\u305f\u306e\u3067\u30e1\u30e2\u3002\u3061\u3087\u3063\u3068\u3057\u305f\u5de5\u592b\u3067\u901f\u304f\u306a\u308b\u307f\u305f\u3044\u3067\u3059\u3002\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u5229\u7528\u3068\u3044\u3046\u306e\u304c\u3061\u3087\u3063\u3068\u610f\u5916\u304b\u3082\u3002 import java.util.Collections; im … \u7d9a\u304d\u3092\u8aad\u3080 →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-777","post","type-post","status-publish","format-standard","hentry","category-java"],"_links":{"self":[{"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/posts\/777","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/comments?post=777"}],"version-history":[{"count":0,"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/posts\/777\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/media?parent=777"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/categories?post=777"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hiro345.net\/blogs\/hiro345\/wp-json\/wp\/v2\/tags?post=777"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}