Finding the Size of Objects in Java
In Java, the question of determining the memory footprint of an object arises frequently when comparing data structures. However, unlike C/C with its sizeOf() method, Java lacks an explicit method for this purpose.
Solution: Utilizing java.lang.instrumentation
The lack of a built-in method in Java necessitates an alternative approach. One suitable solution is to leverage the java.lang.instrumentation package. This package provides a method that delivers an implementation-specific approximation of an object's size, along with any associated overhead.
Code Example:
The following code snippet demonstrates the usage of the java.lang.instrumentation package to retrieve object sizes:
<code class="java">import java.lang.instrument.Instrumentation; public class ObjectSizeFetcher { private static Instrumentation instrumentation; public static void premain(String args, Instrumentation inst) { instrumentation = inst; } public static long getObjectSize(Object o) { return instrumentation.getObjectSize(o); } }</code>
To determine the size of an object, simply use the getObjectSize method:
<code class="java">public class C { private int x; private int y; public static void main(String [] args) { System.out.println(ObjectSizeFetcher.getObjectSize(new C())); } }</code>
The above is the detailed content of How to Determine the Size of Objects in Java?. For more information, please follow other related articles on the PHP Chinese website!

This article analyzes the top four JavaScript frameworks (React, Angular, Vue, Svelte) in 2025, comparing their performance, scalability, and future prospects. While all remain dominant due to strong communities and ecosystems, their relative popul

This article addresses the CVE-2022-1471 vulnerability in SnakeYAML, a critical flaw allowing remote code execution. It details how upgrading Spring Boot applications to SnakeYAML 1.33 or later mitigates this risk, emphasizing that dependency updat

Node.js 20 significantly enhances performance via V8 engine improvements, notably faster garbage collection and I/O. New features include better WebAssembly support and refined debugging tools, boosting developer productivity and application speed.

The article discusses implementing multi-level caching in Java using Caffeine and Guava Cache to enhance application performance. It covers setup, integration, and performance benefits, along with configuration and eviction policy management best pra

Java's classloading involves loading, linking, and initializing classes using a hierarchical system with Bootstrap, Extension, and Application classloaders. The parent delegation model ensures core classes are loaded first, affecting custom class loa

This article explores methods for sharing data between Cucumber steps, comparing scenario context, global variables, argument passing, and data structures. It emphasizes best practices for maintainability, including concise context use, descriptive

Iceberg, an open table format for large analytical datasets, improves data lake performance and scalability. It addresses limitations of Parquet/ORC through internal metadata management, enabling efficient schema evolution, time travel, concurrent w

This article explores integrating functional programming into Java using lambda expressions, Streams API, method references, and Optional. It highlights benefits like improved code readability and maintainability through conciseness and immutability


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Notepad++7.3.1
Easy-to-use and free code editor

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver CS6
Visual web development tools

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment
