<!DOCTYPE html> <html> <head> <meta charset=_html/css

Home

Web Front-end

HTML Tutorial

<!DOCTYPE html> <html> <head> <meta charset=_html/css_WEB-ITnose

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 24, 2016 am 11:29 AM

Java引用和gc.mdown—/Users/wjk/Desktop/笔记

强引用

强引用是我们接触最多的引用，若果是强引用JVM宁愿抛出OOM也不愿回收具有强引用的对象。

软引用

具有软引用的对象，内存空间充足的时候，垃圾回收器不会回收，当内存空间不充足的时候，垃圾回收器回收。

弱引用

在垃圾回收器线程扫描它所管辖的内存区域的过程中，一旦发现了只具有弱引用的对象，不管当前内存空间足够与否，都会回收它的内存。

虚引用

虚引用主要用来跟踪对象被垃圾回收器回收的活动。虚引用与软引用和弱引用的一个区别在于：虚引用必须和引用队列 （ReferenceQueue）联合使用。当垃圾回收器准备回收一个对象时，如果发现它还有虚引用，就会在回收对象的内存之前，把这个虚引用加入到与之关联的引用队列中。

引用队列

软引用、弱引用可以和一个引用队列（ReferenceQueue）联合使用，如果软引用所引用的对象被垃圾回收器回收，Java虚拟机就会把这个软引用加入到与之关联的引用队列中。

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

What is the purpose of the <datalist> element?Mar 21, 2025 pm 12:33 PM

The article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159

What is the purpose of the <progress> element?Mar 21, 2025 pm 12:34 PM

The article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati

What is the purpose of the <meter> element?Mar 21, 2025 pm 12:35 PM

The article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex

What is the purpose of the <iframe> tag? What are the security considerations when using it?Mar 20, 2025 pm 06:05 PM

The article discusses the <iframe> tag's purpose in embedding external content into webpages, its common uses, security risks, and alternatives like object tags and APIs.

What is the viewport meta tag? Why is it important for responsive design?Mar 20, 2025 pm 05:56 PM

The article discusses the viewport meta tag, essential for responsive web design on mobile devices. It explains how proper use ensures optimal content scaling and user interaction, while misuse can lead to design and accessibility issues.

How do I use HTML5 form validation attributes to validate user input?Mar 17, 2025 pm 12:27 PM

The article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.

What are the best practices for cross-browser compatibility in HTML5?Mar 17, 2025 pm 12:20 PM

Article discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.

How do I use the HTML5 <time> element to represent dates and times semantically?Mar 12, 2025 pm 04:05 PM

This article explains the HTML5 <time> element for semantic date/time representation. It emphasizes the importance of the datetime attribute for machine readability (ISO 8601 format) alongside human-readable text, boosting accessibilit

See all articles