{"id":252,"date":"2025-06-24T07:51:40","date_gmt":"2025-06-24T07:51:40","guid":{"rendered":"https:\/\/thetestdata.com\/blog\/?p=252"},"modified":"2025-07-16T10:23:52","modified_gmt":"2025-07-16T10:23:52","slug":"difference-between-array-and-arraylist","status":"publish","type":"post","link":"https:\/\/thetestdata.com\/blog\/difference-between-array-and-arraylist\/","title":{"rendered":"Difference between Array and ArrayList?"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\">An <strong>Array<\/strong> and an <strong>ArrayList<\/strong> in Java\u2014they might sound similar, but they behave quite differently under the hood!<\/h3>\n\n\n\n<p>\ud83e\uddfe Key Differences Between Array and ArrayList<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature<\/th><th>Array<\/th><th>ArrayList<\/th><\/tr><\/thead><tbody><tr><td><strong>Size<\/strong><\/td><td>Fixed when created<\/td><td>Dynamically resizable<\/td><\/tr><tr><td><strong>Syntax<\/strong><\/td><td><code>int[] arr = new int[5];<\/code><\/td><td><code>ArrayList list = new ArrayList&lt;&gt;();<\/code><\/td><\/tr><tr><td><strong>Type Support<\/strong><\/td><td>Can hold primitives (<code>int<\/code>, <code>char<\/code>, etc.)<\/td><td>Only objects (<code>Integer<\/code>, <code>String<\/code>, etc.)<\/td><\/tr><tr><td><strong>Memory Efficiency<\/strong><\/td><td>More memory-efficient (less overhead)<\/td><td>Slightly more memory usage (due to internal structure)<\/td><\/tr><tr><td><strong>Performance<\/strong><\/td><td>Faster in basic operations<\/td><td>Slightly slower due to dynamic resizing<\/td><\/tr><tr><td><strong>Methods<\/strong><\/td><td>No built-in methods beyond index access<\/td><td>Has methods like <code>add()<\/code>, <code>remove()<\/code>, <code>contains()<\/code><\/td><\/tr><tr><td><strong>Length Access<\/strong><\/td><td>Use <code>.length<\/code><\/td><td>Use <code>.size()<\/code><\/td><\/tr><tr><td><strong>Multidimensional?<\/strong><\/td><td>Yes (<code>int[][]<\/code>)<\/td><td>Indirectly with <code>ArrayList&gt;<\/code><\/td><\/tr><tr><td><strong>Thread Safety<\/strong><\/td><td>Not synchronized<\/td><td>Not synchronized (but use <code>Collections.synchronizedList()<\/code> for thread safety)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\ud83d\udee0 Quick Code Comparison<\/p>\n\n\n\n<p>\/\/ Array <\/p>\n\n\n\n<p>int[] numbers = new int[3]; <\/p>\n\n\n\n<p>numbers[0] = 10; <\/p>\n\n\n\n<p>\/\/ ArrayList <\/p>\n\n\n\n<p>ArrayList list = new ArrayList&lt;>(); <\/p>\n\n\n\n<p>list.add(10);<\/p>\n\n\n\n<p>\ud83e\udde0 Which One Should You Use?<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use <strong>Array<\/strong> when:<br>You know the size in advance, and performance is critical.<\/li>\n\n\n\n<li>Use <strong>ArrayList<\/strong> when:<br>You want dynamic sizing, easy insertion\/removal, and rich built-in methods.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Explore the difference between Array and ArrayList in Java. Learn how fixed-size arrays compare to dynamic ArrayLists in flexibility, performance, and usage<\/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,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-container-style":"default","site-container-layout":"default","site-sidebar-layout":"default","disable-article-header":"default","disable-site-header":"default","disable-site-footer":"default","disable-content-area-spacing":"default","footnotes":""},"categories":[17],"tags":[],"class_list":["post-252","post","type-post","status-publish","format-standard","hentry","category-java-interview-questions"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts\/252","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/comments?post=252"}],"version-history":[{"count":2,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts\/252\/revisions"}],"predecessor-version":[{"id":446,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts\/252\/revisions\/446"}],"wp:attachment":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/media?parent=252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/categories?post=252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/tags?post=252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}