{"id":14207,"date":"2024-03-15T08:40:43","date_gmt":"2024-03-15T08:40:43","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-modify-objects-in-an-arraylist-using-java\/"},"modified":"2025-08-06T05:25:35","modified_gmt":"2025-08-06T05:25:35","slug":"how-to-modify-objects-in-an-arraylist-using-java","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-modify-objects-in-an-arraylist-using-java\/","title":{"rendered":"How to modify objects in an ArrayList using Java?"},"content":{"rendered":"<p>To modify an object in an ArrayList, first you need to retrieve the object, then make the modifications, and finally put the modified object back into the ArrayList. Here is an example code snippet:<\/p>\n<pre class=\"post-pre\"><code><span class=\"hljs-keyword\">import<\/span> java.util.ArrayList;\r\n\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">Main<\/span> {\r\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">main<\/span><span class=\"hljs-params\">(String[] args)<\/span> {\r\n        <span class=\"hljs-comment\">\/\/ \u521b\u5efa\u4e00\u4e2aArrayList\u5bf9\u8c61<\/span>\r\n        ArrayList&lt;Student&gt; studentList = <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">ArrayList<\/span>&lt;&gt;();\r\n\r\n        <span class=\"hljs-comment\">\/\/ \u6dfb\u52a0Student\u5bf9\u8c61\u5230ArrayList\u4e2d<\/span>\r\n        studentList.add(<span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">Student<\/span>(<span class=\"hljs-string\">\"Alice\"<\/span>, <span class=\"hljs-number\">18<\/span>));\r\n        studentList.add(<span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">Student<\/span>(<span class=\"hljs-string\">\"Bob\"<\/span>, <span class=\"hljs-number\">20<\/span>));\r\n        studentList.add(<span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">Student<\/span>(<span class=\"hljs-string\">\"Charlie\"<\/span>, <span class=\"hljs-number\">22<\/span>));\r\n\r\n        <span class=\"hljs-comment\">\/\/ \u4fee\u6539ArrayList\u4e2d\u7684\u5bf9\u8c61<\/span>\r\n        <span class=\"hljs-comment\">\/\/ \u9996\u5148\u627e\u5230\u8981\u4fee\u6539\u7684\u5bf9\u8c61<\/span>\r\n        <span class=\"hljs-keyword\">for<\/span> (Student student : studentList) {\r\n            <span class=\"hljs-keyword\">if<\/span> (student.getName().equals(<span class=\"hljs-string\">\"Bob\"<\/span>)) {\r\n                <span class=\"hljs-comment\">\/\/ \u4fee\u6539\u5bf9\u8c61\u7684\u5c5e\u6027<\/span>\r\n                student.setAge(<span class=\"hljs-number\">21<\/span>);\r\n                <span class=\"hljs-keyword\">break<\/span>; <span class=\"hljs-comment\">\/\/ \u627e\u5230\u5bf9\u8c61\u540e\u8df3\u51fa\u5faa\u73af<\/span>\r\n            }\r\n        }\r\n\r\n        <span class=\"hljs-comment\">\/\/ \u6253\u5370\u4fee\u6539\u540e\u7684ArrayList<\/span>\r\n        <span class=\"hljs-keyword\">for<\/span> (Student student : studentList) {\r\n            System.out.println(student.getName() + <span class=\"hljs-string\">\" - \"<\/span> + student.getAge());\r\n        }\r\n    }\r\n}\r\n\r\n<span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">Student<\/span> {\r\n    <span class=\"hljs-keyword\">private<\/span> String name;\r\n    <span class=\"hljs-keyword\">private<\/span> <span class=\"hljs-type\">int<\/span> age;\r\n\r\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-title function_\">Student<\/span><span class=\"hljs-params\">(String name, <span class=\"hljs-type\">int<\/span> age)<\/span> {\r\n        <span class=\"hljs-built_in\">this<\/span>.name = name;\r\n        <span class=\"hljs-built_in\">this<\/span>.age = age;\r\n    }\r\n\r\n    <span class=\"hljs-keyword\">public<\/span> String <span class=\"hljs-title function_\">getName<\/span><span class=\"hljs-params\">()<\/span> {\r\n        <span class=\"hljs-keyword\">return<\/span> name;\r\n    }\r\n\r\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">setName<\/span><span class=\"hljs-params\">(String name)<\/span> {\r\n        <span class=\"hljs-built_in\">this<\/span>.name = name;\r\n    }\r\n\r\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-type\">int<\/span> <span class=\"hljs-title function_\">getAge<\/span><span class=\"hljs-params\">()<\/span> {\r\n        <span class=\"hljs-keyword\">return<\/span> age;\r\n    }\r\n\r\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">setAge<\/span><span class=\"hljs-params\">(<span class=\"hljs-type\">int<\/span> age)<\/span> {\r\n        <span class=\"hljs-built_in\">this<\/span>.age = age;\r\n    }\r\n}\r\n<\/code><\/pre>\n<p>First, an ArrayList object studentList is created in the above example code, which contains three Student objects. Then, the object to be modified is found by iterating through the ArrayList, and its attributes are modified using the setAge method. Finally, the modified object information is printed by iterating through the ArrayList again.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>To modify an object in an ArrayList, first you need to retrieve the object, then make the modifications, and finally put the modified object back into the ArrayList. Here is an example code snippet: import java.util.ArrayList; public class Main { public static void main(String[] args) { \/\/ \u521b\u5efa\u4e00\u4e2aArrayList\u5bf9\u8c61 ArrayList&lt;Student&gt; studentList = new ArrayList&lt;&gt;(); \/\/ \u6dfb\u52a0Student\u5bf9\u8c61\u5230ArrayList\u4e2d [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[453,1402,299,1404,1403],"class_list":["post-14207","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-development","tag-guide","tag-programming","tag-technology","tag-tutorial"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to modify objects in an ArrayList using Java? - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Learn about how to modify objects in an arraylist using java?. 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