garbage collection
jdk8gc机制
jdk8gc机制JDK 8的GC机制JDK 8（Java Development Kit 8）是Java平台的一个版本，其中包含了许多新的特性和改进。
其中一个重要的改进就是对垃圾回收（Garbage Collection，GC）机制的优化。
GC是Java内存管理的关键部分，它负责自动回收不再使用的对象，释放内存空间，以避免内存泄漏和程序崩溃。
在JDK 8中，GC机制经历了一些重大的改进和优化，以提高性能和减少内存占用。
下面将介绍一些JDK 8的GC机制的特点和优势。
1. G1垃圾回收器（Garbage First Garbage Collector）：JDK 8引入了一种新的垃圾回收器，即G1垃圾回收器。
相比于之前的垃圾回收器，G1垃圾回收器具有更好的吞吐量和更低的延迟。
它能够自动监控各个内存区域的垃圾情况，并根据垃圾情况进行动态调整，以实现更高效的垃圾回收。
2. 基于Region的内存管理：JDK 8将堆内存分成了许多大小相等的区域（Region），每个区域独立管理。
这种基于Region的内存管理方式使得GC操作更加高效，可以更细粒度地管理内存，减少内存碎片。
同时，它还可以将GC操作分散到多个线程上，以提高并发性能。
3. 并行和并发回收：JDK 8的GC机制充分利用了多核处理器的并行能力。
它可以同时使用多个线程进行垃圾回收操作，以加快回收速度。
同时，它还引入了一些并发回收的策略，使得垃圾回收操作与应用程序的执行可以同时进行，减少了停顿时间，提高了用户体验。
4. 元空间代替永久代：JDK 8取消了永久代（PermGen）的概念，取而代之的是元空间（Metaspace）。
永久代是用于存储类的元数据信息的，而元空间则是使用本地内存（Native Memory）来存储类的元数据信息。
这种改变解决了永久代容易出现内存溢出的问题，提高了内存的利用率。
5. 垃圾回收日志和诊断工具：JDK 8提供了更丰富的垃圾回收日志和诊断工具，可以帮助开发人员更好地理解和分析程序的垃圾回收情况。
文献综述(垃圾的可回收)英文版
Literature review of garbage collection——李薇，李灿，唐兰心，猫然IntroductionPurpose ：For garbage recycling, the status quo at home and abroad, due to different start, the maturity of garbage disposal capacity and system is also different. Overseas countries have accumulated rich experience, while China's recycling technology is currently only piloted in a few cities, with few application examples. The author summarized and sorted out the references at home and abroad, analyzed the representative articles at home and abroad respectively, and elaborated the viewpoint and development trend of garbage recycling in this kind of articles, and then found the way to realize garbage recycling in our country.Measure：Using SCI and CNKI databases, our team searched relevant journals with garbage recycling as the key word, classified and summarized the relevant journals, and carried out a literature survey on the topic of garbage recycling under the reasonable division of labor and coordination, and summarized the literature survey.Domestic garbage collection status1. At present, the old ways of municipal solid waste treatment in China are mainly landfill, compost and incineration.2. Residents' individual factors, including the lack of knowledge of garbage classification, lack of corresponding knowledge of garbage classification. At present, the knowledge of garbage classification of most residents in China isrelatively simple or even one-sided. Few people can consciously and actively classify garbage.3. Garbage collection facilities classification confusion4. There are also problems in the implementation of garbage classification system. Although the garbage classification Department has made the garbage bin classification system in the district beforehand, the municipal sanitation department will merge the garbage in order to save labor during the recycling process. This "even pot end" method has seriously affected residents' confidence in independent garbage classification, but also greatly offset the effect ofpre-resident garbage classification, resulting in a certain malignant effect.4.Some matching systems of garbage classification are not perfect. Such as rewards and punishment mechanism, propaganda and education system and other defects.5. The cost of garbage collection is higher.6. The results are not obvious: since the original Ministry of Construction announced the list of the first pilot cities for sorting and collecting domestic waste in 2000, nearly 20 years have passed. Although cities have been exploring new models for garbage control, it is undeniable that the results are not obvious. The average annual garbage output per city is 440 kilograms. 600 cities in the country generate 80 million tons of garbage.参考文献1.城市生活垃圾焚烧社会成本评估方法与应用——以北京市为例宋国君、孙月阳、赵畅、刘帅、王颖著Author's Institutions: School of Environment, Renmin University of China; School of Management Cadres, Ministry of Agriculture; Hebei Dezheng Law Firm2.中国实施垃圾分类为何这么难？——刘庆健著2. 垃圾分类与垃圾治理研究, Zhejiang Gongshang University press, 2018.01, second ------方建移著3.广东省农村垃圾产生特征及处理方式的调查分析Writers：高海硕;陈桂葵；黎华寿等Journal of Rural Environmental Science Volume: 31 issue: 7 pages: 1445-1452 Document No. 1672-2043 (2012)4.基于RBF网络的城市垃圾产量预测及可视化秦绪佳、彭洁、徐菲、郑红波、张美玉著Necessity of garbage collection1.Harmfulness of the old methods of Disposing Municipal Solid waste: At present, the old methods of landfill, composting and incineration are still the main ways of Disposing Municipal Solid Waste in China. Most of these traditional methods have some disadvantages, such as waste of land resources, high technical requirements of composting, secondary pollution caused by incineration, etc.2.High proportion of recyclable resources: Due to the characteristics of campus environment, waste generated by college students ' life mainly includes:Paper products, plastic products, a small amount of metal products and kitchen waste. Covered in teaching, living, dormitory, outdoorSite area. There are 2763 institutions of higher learning in China and about thirty million of college students.Nearly 20,000 tons, of which the proportion of recoverable resources is very high, should be well classified recovery.3. garbage accumulation seriously affects urban development.4. human happiness index and national significance5. The significance of garbage classification and garbage treatment lies not only in solving the dilemma of garbage siege, but also in solving it.It lies in the environmental protection itself, and its significance also includesadvocating and forming a healthy lifestyle and promoting the livelihood of the people.Quality of Life and Subjective Well-being, Promoting Governing Ability and Public Credit of the Government, Improving National Quality and Public MoralityRecognize and improve China's international image in order to realize the "strive to build a beautiful China and realize it" put forward by the Eighteenth National Congress of the Communist Party of ChinaThe goal of sustainable development of the Chinese nation.参考文献1.垃圾分类与垃圾治理研究Zhejiang Gongshang University press, 2018.01, second pages. ------方建移著，2.生活垃圾分类制度设计研究：以杭州市为例------颜安庆，蒋晓琦，朱诗雨，丁丁，张鸿昌，李冰洁著，The methods of Garbage collectionTechnical means1.Intelligent System for Garbage collection: IOT technology with Ultrasonic sensor and Arduino Mega . To avoid the piles of rubbish , a project called IOT Based Smart Garbage System I will be implemented, which can be generate warning message to the municipality via SMS when the garbage bin is full or almost full, so the garbage can be collected immediately.2. Fully implementing the dichotomy of dry and wet3. Smart garbage monitoring system for waste management 。
gc监控指标 -回复
gc监控指标-回复GC（Garbage Collection）是指垃圾回收，是一种自动内存管理机制，用于检测和回收不再使用的内存。
在Java应用程序中，垃圾收集器是负责管理堆内存中对象的分配和释放的，以确保应用程序有效地使用内存资源。
GC监控指标是用于监视和分析GC行为的一系列度量指标，可以帮助我们了解垃圾收集器的性能表现、内存使用情况和应用程序的健康状况。
以下是一些常见的GC监控指标和它们的解释：1. 垃圾收集时间（GC Time）：垃圾收集器在执行垃圾回收时花费的时间。
高垃圾收集时间可能会导致应用程序的停顿时间增加，降低应用程序的响应性能。
2. 垃圾收集器执行次数（GC Count）：记录垃圾收集器执行垃圾回收的次数。
高垃圾收集器执行次数可能意味着堆内存的使用情况不佳，或者可能存在内存泄漏的问题。
3. 垃圾收集器执行耗时（GC Latency）：衡量垃圾收集器执行垃圾回收所花费的时间。
高垃圾收集器执行耗时可能会导致应用程序的停顿时间增加，影响应用程序的性能。
4. 垃圾回收器堆内存使用量（Heap Usage）：记录堆内存的使用情况，包括堆内存的总容量、已使用容量和剩余容量。
高垃圾回收器堆内存使用量可能意味着内存使用不均衡，或者可能存在内存泄漏的问题。
5. 内存分配速率（Allocation Rate）：记录在单位时间内分配的新对象的数量。
高内存分配速率可能会导致频繁的垃圾回收，增加垃圾收集器的负担。
6. 晋升对象数量（Promotion Count）：记录从新生代到老年代晋升的对象数量。
过多的晋升对象可能会导致老年代的内存使用过于频繁，增加垃圾收集器的工作量。
7. 年轻代回收频率（Young Generation Collection Frequency）：记录年轻代（包括Eden区和Survivor区）垃圾回收的频率。
过于频繁的年轻代回收可能会对应用程序的性能产生负面影响。
8. 老年代回收频率（Old Generation Collection Frequency）：记录老年代垃圾回收的频率。
js垃圾回收机制原理
js垃圾回收机制原理JavaScript是一种高级编程语言，常用于编写Web应用程序。
与其他语言不同，JavaScript具有自动垃圾回收（Garbage Collection，简称GC）机制，它可以自动管理内存并处理不再使用的对象和变量。
垃圾回收的目标是识别并清除不再使用的内存，以便其他程序可以使用。
JavaScript引擎通过使用多种垃圾回收算法来实现这一目标。
在此文章中，我们将介绍一些常见的垃圾回收机制原理。
1. 引用计数（Reference Counting）垃圾回收机制：这是一种简单的垃圾回收机制，它通过跟踪每个对象的引用数量来判断该对象是否不再使用。
当一个对象没有任何引用时，它就可以被认为是垃圾，会被垃圾回收器清除。
然而，这种机制可能会导致循环引用的问题，即两个或多个对象互相引用时，它们的引用计数不会达到0，即使它们都无法被访问。
2. 标记-清除（Mark-and-Sweep）垃圾回收机制：这是一种更常见和高效的垃圾回收机制。
它通过遍历根对象，然后递归地找到所有可访问的对象，并将它们标记为“活动”状态。
一旦标记完成，垃圾回收器会清除所有未被标记的对象，这些对象将被认为是垃圾。
标记-清除机制可以解决引用计数的循环引用问题，并且只清除不再使用的对象。
3. 分代回收（Generational Collection）：分代回收是一种改进的标记-清除机制，它假设大多数对象没有长时间存活的倾向。
根据这一假设，垃圾回收器将内存分为不同的代，如新生代和老生代。
新生代包含生命周期较短的对象，而老生代包含生命周期较长的对象。
垃圾回收器会优先清除新生代中的对象，因为它们更有可能是垃圾。
只有当新生代的垃圾回收不足以满足内存需求时，才会清除老生代的对象。
分代回收机制的核心思想是，较新的对象更容易成为垃圾。
4. 增量回收（Incremental Collection）：垃圾回收器通常在整个应用程序暂停执行时运行，以便进行全面的垃圾回收。
GC原理与构造
GC原理与构造GC（Garbage Collection）是指垃圾回收的意思，是计算机科学中的一个概念和技术。
在计算机程序执行过程中，会产生一些不再使用的对象，这些对象占用了内存资源，但是却无法通过程序来访问和使用。
为了释放这些无用的对象占用的内存，避免内存泄漏和内存溢出的发生，需要进行垃圾回收。
垃圾回收的原理是通过判断对象是否可达来判断其是否是垃圾。
垃圾回收器会从根对象开始遍历对象图，标记所有可达的对象。
经过标记的对象被认为是活动的对象，而没有标记的对象被认为是垃圾。
垃圾回收器会将这些垃圾对象占用的内存进行回收，以便其他对象可以使用。
垃圾回收的构造包括以下几个重要的组成部分：1. 根集合（Root Set）：根集合是垃圾回收的起点，包括全局变量、栈上的变量和寄存器中的变量。
垃圾回收器从根集合开始遍历并标记可达对象，以便判断其是否是垃圾。
2. 引用计数（Reference Counting）：引用计数是一种简单而常用的垃圾回收算法。
它通过为每个对象维护一个引用计数器，当对象被引用时计数器加1，当引用被释放时计数器减1、当计数器为0时，对象被认为是垃圾。
这种算法简单高效，但是无法处理循环引用的情况。
3. 可达性分析（Reachability Analysis）：可达性分析是一种常用的垃圾回收算法，用于标记可达对象。
垃圾回收器从根集合开始遍历对象图，标记所有可达对象，而没有被标记的对象则被认为是垃圾。
5. 收集器（Collector）：收集器是实现垃圾回收的具体程序。
根据垃圾回收的需求和应用场景的不同，可以选择不同类型的收集器，如串行收集器、并行收集器、并发收集器等。
除了以上的基本原理和构造，GC还涉及到一些额外的概念和技术，如分代收集（Generational Collection）、增量回收（Incremental Collection）、并发回收（Concurrent Collection）等。
垃圾收集英文作文
垃圾收集英文作文英文：Garbage collection is an important aspect of waste management. It involves the collection, transportation, and disposal of waste materials in a safe and efficient manner. There are various methods of garbage collection, including curbside pickup, drop-off centers, and recycling programs.Curbside pickup is the most common method of garbage collection in residential areas. This involves placing garbage and recycling bins at the curb on designated pickup days. The garbage is then collected by a waste management company and transported to a landfill or recycling center.Drop-off centers are another method of garbage collection. These centers are typically located in commercial areas and allow residents to drop off their waste materials for proper disposal. Recycling programs are also becoming more popular, as they encourage residents toseparate recyclable materials from their regular garbage and dispose of them in designated recycling bins.Proper garbage collection is important for several reasons. It helps to prevent pollution and protect the environment by ensuring that waste materials are disposed of in a safe and efficient manner. It also helps to reduce the amount of waste that ends up in landfills, which can have negative impacts on public health and the environment.In addition to traditional garbage collection methods, there are also new technologies being developed to improve waste management. For example, some cities are experimenting with smart waste management systems that use sensors to monitor garbage levels in bins and optimize collection routes.Overall, garbage collection is an essential component of waste management that helps to protect the environment and promote public health.中文：垃圾收集是废物管理的重要方面。
收集垃圾英语作文
收集垃圾英语作文In the modern era, where urbanization is rapidly expanding,the issue of waste management has become a critical concernfor sustainable living. Garbage collection, a fundamental aspect of waste management, plays a pivotal role inmaintaining the cleanliness and health of our communities.This essay will explore the importance of garbage collection, the challenges faced, and the potential solutions to improve this essential service.Firstly, garbage collection is essential for environmental conservation. The improper disposal of waste can lead to pollution of soil, water, and air, which in turn harms the ecosystem and human health. By systematically collecting and disposing of waste, we prevent the release of harmful substances into the environment, thus preserving the natural habitats of various species and ensuring a cleaner, safer planet for future generations.Secondly, garbage collection is a key component inmaintaining public health. Accumulated waste can become a breeding ground for disease-carrying pests such as rodentsand insects. Regular collection and disposal of garbage helpto control the population of these vectors, thereby reducing the spread of diseases like dengue, malaria, and other illnesses associated with poor sanitation.Moreover, garbage collection is not just about removing waste;it is also about recycling and reusing materials. Many items that we discard can be recycled into new products, reducingthe need for raw materials and the energy required to produce them. This not only conserves natural resources but alsohelps in reducing the carbon footprint associated with manufacturing new goods.However, garbage collection faces numerous challenges. One of the primary issues is the lack of awareness among the public about the proper sorting and disposal of waste. Many peopleare unaware of the different categories of waste, such as recyclables, compostables, and non-recyclables, leading to improper disposal and contamination of recyclable materials.Additionally, the infrastructure for garbage collection in some areas is inadequate. There may be a shortage ofcollection vehicles, insufficient waste processing facilities, or a lack of trained personnel to manage the system effectively. These issues can result in delays and inefficiencies in the garbage collection process.To address these challenges, several solutions can be implemented. Education and awareness campaigns can be conducted to inform the public about the importance of proper waste disposal and the benefits of recycling. Local governments can invest in better infrastructure, such as more collection vehicles and advanced waste processing facilities, to improve the efficiency of garbage collection services.In conclusion, garbage collection is a vital service that contributes significantly to the well-being of ourcommunities and the environment. By understanding its importance, addressing the challenges, and implementing effective solutions, we can ensure a cleaner, healthier, and more sustainable future for all.。
支持垃圾回收英文作文
支持垃圾回收英文作文1. Garbage collection is the bomb! Seriously, it's like having a personal assistant who takes care of all your trash for you. You don't have to worry about sorting it or finding a place to dispose of it properly. Just toss it in the bin and forget about it. It's such a relief to knowthat someone else is taking care of the mess for you.2. I mean, think about it. Without garbage collection, we would be drowning in our own waste. Can you imagine the stench and the unsanitary conditions? It would be a nightmare. But thanks to this amazing system, our neighborhoods stay clean and healthy. We can enjoy our surroundings without worrying about the garbage piling up.3. Another great thing about garbage collection is that it promotes recycling. When you know that your trash will be sorted and recycled, it encourages you to be more conscious of what you throw away. It's like a gentle reminder to reduce, reuse, and recycle. Plus, it's sosatisfying to see those recycling bins being emptied and knowing that your efforts are making a difference.4. Garbage collection also helps to protect the environment. When waste is disposed of properly, it minimizes the risk of pollution and contamination. It ensures that harmful substances don't end up in our waterways or soil, which can have devastating effects on plants, animals, and even our own health. So, in a way, garbage collection is like a superhero saving the planet.5. Let's not forget about the convenience factor. Can you imagine having to drive to a landfill every time you had garbage to dispose of? It would be such a hassle. But with garbage collection, all you have to do is put your trash out on the designated day, and it magically disappears. It's like having your own personal trash fairy.6. Lastly, garbage collection is a job creator. Think about all the people employed in this industry. From the drivers who pick up the trash to the workers at the recycling facilities, it provides employment opportunitiesfor many individuals. So not only does it benefit us as individuals, but it also contributes to the economy.In conclusion, garbage collection is a vital service that we often take for granted. It keeps our communities clean, promotes recycling, protects the environment, provides convenience, and creates jobs. So let's give a big shout-out to all the garbage collectors out there. You guys rock!。
垃圾回收英语作文
垃圾回收英语作文Garbage Collection.I hate garbage. It smells bad and attracts flies. It's disgusting to see trash lying around, polluting the environment. We need to do something about it.There are so many different types of garbage. There's food waste, plastic bottles, paper, and so much more. It's overwhelming to think about how much garbage we produce every day. We need to find a way to reduce our waste.One solution is recycling. Recycling is a great way to reduce the amount of garbage that ends up in landfills. We can recycle paper, plastic, glass, and even electronics.It's important to separate our trash and put it in theright recycling bins.Another solution is composting. Composting is a natural way to break down organic waste, like food scraps and yardtrimmings. It creates nutrient-rich soil that can be used in gardens and farms. Composting is a simple and effective way to reduce waste and help the environment.We also need to educate people about the importance of garbage collection. Many people don't realize the impact that their trash has on the environment. We need to teach them about the consequences of littering and the benefits of proper waste disposal.In addition to recycling and composting, we can also reduce waste by reusing items. Instead of throwing things away, we can find creative ways to give them a second life. We can donate clothes and furniture to charity, or repurpose old items into something new.It's time for us to take action and make a change. We need to come together as a community and prioritize garbage collection. Let's clean up our neighborhoods and protect our planet. It's not just about us, but also about future generations.In conclusion, garbage is a big problem that we need to address. Recycling, composting, and reusing are all effective ways to reduce waste. We also need to educate people about the importance of proper garbage collection. Let's work together to create a cleaner and healthier environment for everyone.。
垃圾收购站英语作文
垃圾收购站英语作文Garbage Collection Station。
Garbage collection stations play a crucial role in managing waste and promoting environmental sustainability. These facilities serve as a central hub for collecting, sorting, and processing various types of waste materials, including recyclables, organic waste, and hazardous materials. By providing a convenient and efficient way for individuals and businesses to dispose of their waste responsibly, garbage collection stations help reduce pollution, conserve resources, and protect public health.One of the key functions of a garbage collectionstation is to separate different types of waste materials for recycling or proper disposal. This process involves sorting items such as paper, plastic, glass, and metal into designated bins or containers to prevent contamination and facilitate recycling. By diverting recyclable materials from landfills and incinerators, garbage collectionstations help conserve natural resources, reduce energy consumption, and minimize greenhouse gas emissions.In addition to recycling, garbage collection stations also play a vital role in managing organic waste, such as food scraps, yard trimmings, and other biodegradable materials. By composting organic waste on-site orpartnering with local composting facilities, these stations can divert valuable nutrients from landfills and create nutrient-rich soil amendments for gardening and agriculture. Composting organic waste not only reduces methane emissions from landfills but also helps improve soil health, conserve water, and support local food production.Furthermore, garbage collection stations provide a safe and convenient way for individuals to dispose of hazardous materials, such as batteries, electronics, chemicals, and pharmaceuticals. These facilities often have special collection programs or drop-off locations for hazardous waste to prevent environmental contamination and protect public health. By properly managing hazardous materials, garbage collection stations help prevent pollution, reducethe risk of toxic exposure, and safeguard ecosystems for future generations.Overall, garbage collection stations play a critical role in promoting waste reduction, resource conservation, and environmental protection. By providing essential services for collecting, sorting, and processing waste materials, these facilities help communities achieve their sustainability goals and build a cleaner, healthier, and more resilient future. As individuals, businesses, and governments work together to support garbage collection stations and adopt sustainable waste management practices, we can create a more circular economy and a greener planet for all.。
垃圾收集英文作文
垃圾收集英文作文Title: The Importance of Garbage Collection: A Comprehensive Analysis。
Introduction。
Garbage collection, also known as waste disposal or waste management, plays a pivotal role in maintaining cleanliness, hygiene, and environmental sustainability in our communities. This essay delves into the significance of garbage collection, its challenges, and potential solutions.Importance of Garbage Collection。
Garbage collection is crucial for several reasons. Firstly, it prevents the accumulation of waste, which ifleft unattended, can lead to health hazards, pollution, and environmental degradation. Proper disposal of waste reduces the risk of diseases caused by vermin and pathogensbreeding in garbage heaps.Secondly, efficient garbage collection contributes to the aesthetic appeal of our surroundings. Clean streets, parks, and neighborhoods enhance the quality of life and promote a sense of pride and belonging among residents.Moreover, garbage collection is essential for the conservation of natural resources. Through recycling and proper disposal methods, valuable materials can be reclaimed and reused, reducing the strain on finite resources and minimizing the need for raw material extraction.Challenges in Garbage Collection。
垃圾回收的重要性英语作文
垃圾回收的重要性英语作文英文回答：Garbage collection is extremely important for maintaining a clean and healthy environment. Without proper garbage collection, waste can pile up and lead to pollution, disease, and other negative consequences. In my opinion,the importance of garbage collection cannot be overstated.One reason why garbage collection is so important is because it helps to prevent the spread of disease. For example, if garbage is not collected and disposed of properly, it can attract pests like rats and flies, which can carry harmful bacteria and viruses. This can lead tothe spread of diseases like typhoid, cholera, and dengue fever. By regularly collecting and disposing of garbage, we can help to prevent the spread of these diseases andprotect public health.Another reason why garbage collection is important isbecause it helps to protect the environment. When garbageis left to pile up, it can contaminate soil and water sources, leading to pollution and harm to wildlife. For example, plastic waste can end up in the ocean, where it can harm marine animals like turtles and seabirds. By properly collecting and disposing of garbage, we can help to reduce pollution and protect the natural environment.In addition to preventing disease and protecting the environment, garbage collection also helps to create a clean and pleasant living environment. Nobody wants to live in a place that is filled with garbage and waste. By regularly collecting and disposing of garbage, we can ensure that our communities are clean, safe, and attractive places to live.Overall, garbage collection plays a crucial role in maintaining a clean and healthy environment. It isessential for preventing disease, protecting the environment, and creating a pleasant living environment for all.中文回答：垃圾回收对于维护清洁健康的环境至关重要。
垃圾回收的好处作文
垃圾回收的好处作文英文回答：Garbage collection is a crucial process that helps to keep our environment clean and healthy. There are several benefits of garbage collection that contribute to a better quality of life for everyone.First and foremost, garbage collection helps to prevent the spread of diseases. When trash is left to pile up, it can attract pests like rats and flies, which can carry harmful bacteria and viruses. By regularly collecting and disposing of garbage, we can reduce the risk of diseases spreading in our communities.Secondly, garbage collection helps to preserve natural resources. When we recycle and properly dispose of our waste, we can reduce the need for raw materials to be extracted from the earth. This helps to conserve resources like water, minerals, and energy, which are essential forsustaining life on our planet.Additionally, garbage collection plays a key role in reducing pollution. Improperly disposed of garbage can contaminate soil, water, and air, leading to environmental degradation and health hazards. By collecting and disposing of garbage in a responsible manner, we can help to minimize pollution and protect our ecosystems.Moreover, garbage collection promotes a sense of community pride and responsibility. When we see our neighborhoods clean and free of litter, it instills a sense of pride in where we live. It also encourages us to take ownership of our environment and work together to keep it clean and beautiful.In conclusion, garbage collection is essential for maintaining a clean and healthy environment. By properly managing our waste, we can prevent the spread of diseases, conserve natural resources, reduce pollution, and foster a sense of community pride. It is a simple yet impactful way to make a positive difference in our world.中文回答：垃圾回收是一个至关重要的过程，有助于保持我们的环境清洁和健康。
环卫工人的单词
环卫工人的单词环卫工人是城市清洁工作中至关重要的一环，他们负责保持城市的卫生和环境的整洁。
作为环卫工人，他们需要掌握一些与工作相关的专业词汇，以便更好地完成工作任务。
在下面的文章中，我将介绍一些与环卫工作相关的常用单词。
1. 垃圾分类 (Waste Sorting)垃圾分类是环卫工作中至关重要的任务之一。
它指的是将垃圾根据不同的属性和材料进行分离，以便后续处理和回收利用。
环卫工人需要掌握各种垃圾的分类方法和相应的术语，如可回收垃圾(Recyclable Waste)、有害垃圾(Hazardous Waste)、湿垃圾 (Organic Waste)和干垃圾 (Non-organic Waste)等。
2. 垃圾清理 (Garbage Collection)垃圾清理是环卫工人日常工作的核心内容之一。
他们需要将垃圾从各个公共区域收集起来，并将其运送到指定的垃圾处理设施。
与垃圾清理相关的词汇包括垃圾车 (Garbage Truck)、垃圾箱 (Garbage Bin)、清运 (Garbage Collection)和清扫(Sweeping)等。
3. 道路清洁 (Street Cleaning)道路清洁是保持城市整洁的重要任务。
环卫工人会清除道路上的垃圾、积水和杂物，以确保行人和车辆的安全。
与道路清洁相关的单词有清洁剂 (Cleaning Agent)、扫帚 (Broom)、洒水车 (Watering Truck)和清洁工具 (Cleaning Equipment)等。
4. 污水处理 (Sewage Treatment)环卫工人还需要参与污水处理工作。
他们负责清理和维护城市污水管道系统，以确保污水得到适当的处理和排放，保护环境免受污染。
与污水处理相关的词汇包括污水处理厂 (Sewage Treatment Plant)、管道清理 (Pipe Cleaning)、污泥 (Sewage Sludge)和污水处理设备 (Sewage Treatment Equipment)等。
我们要捡垃圾作文英语
我们要捡垃圾作文英语Title: The Importance of Garbage Collection: A Call to Action。
In our modern world, the issue of garbage collection has become increasingly pressing. With rapid urbanization and industrialization, the volume of waste generated has reached alarming levels. Despite various efforts to promote recycling and waste management, the problem persists. In this essay, I will delve into the importance of garbage collection and advocate for collective action to address this critical issue.First and foremost, effective garbage collection is essential for maintaining public health and environmental sustainability. Improper disposal of waste can lead to contamination of water sources, air pollution, and the spread of diseases. In densely populated areas, inadequate garbage collection infrastructure can result in unsanitary conditions, posing significant health risks to residents.Therefore, investing in comprehensive garbage collection systems is crucial for safeguarding public health and preserving the environment.Furthermore, proper garbage collection is vital for the conservation of natural resources. Many materials used in everyday products, such as paper, plastic, and glass, canbe recycled and reused. By implementing efficient recycling programs and promoting responsible waste disposal practices, we can reduce the demand for raw materials and minimize the strain on natural ecosystems. This not only conserves valuable resources but also helps mitigate theenvironmental impact of resource extraction and manufacturing processes.Moreover, garbage collection plays a pivotal role in mitigating climate change. The decomposition of organic waste in landfills produces methane, a potent greenhousegas that contributes to global warming. By divertingorganic waste from landfills through composting and anaerobic digestion, we can significantly reduce methane emissions and mitigate climate change. Additionally, properwaste management practices, such as recycling and waste-to-energy initiatives, can help reduce our reliance on fossil fuels and promote the transition to a low-carbon economy.Despite the undeniable importance of garbage collection, many communities around the world continue to face challenges in implementing effective waste management strategies. Limited funding, inadequate infrastructure, and insufficient public awareness are some of the barriers that hinder progress in this area. To address these challenges, concerted efforts are needed at the local, national, and global levels.Governments play a crucial role in establishingpolicies and regulations to promote proper waste management practices. By providing incentives for recycling, imposing penalties for illegal dumping, and investing ininfrastructure for waste collection and recycling, governments can create an enabling environment for sustainable waste management. Moreover, public educationand awareness campaigns are essential for changingattitudes and behaviors towards waste disposal. Byeducating individuals about the importance of recycling, composting, and reducing waste generation, we can foster a culture of environmental stewardship and collective responsibility.In addition to government action, the private sector and civil society also have a significant role to play in addressing the garbage collection challenge. Businesses can adopt sustainable practices throughout their supply chains, such as reducing packaging waste and implementing recycling programs. Non-governmental organizations and community groups can organize clean-up campaigns, promote recycling initiatives, and advocate for policy changes to improve waste management systems.In conclusion, garbage collection is a critical issue that requires urgent attention and action. By investing in comprehensive waste management infrastructure, promoting recycling and composting initiatives, and raising public awareness about the importance of responsible waste disposal, we can build a more sustainable future for generations to come. It is only through collective actionand collaboration that we can effectively address the challenges of garbage collection and create a cleaner, healthier planet for all.。
arthas dashboard 的 memory说明 -回复
arthas dashboard 的memory说明-回复Arthas是一款由阿里巴巴开源的Java诊断工具，其dashboard模块提供了对Java应用程序内存使用情况的分析和监控。
在dashboard中，Memory一栏提供了关于应用程序内存的详细信息，帮助开发人员识别和解决内存相关的问题。
本文将逐步解释Arthas dashboard的Memory 说明，并探讨如何有效地利用这些信息来优化Java应用程序的内存管理。
1. Memory Overview (内存概览)Arthas的dashboard提供了一个内存概览面板，展示了Java应用程序的整体内存使用情况。
这个面板提供了几个重要的指标，包括Heap Memory（堆内存）、Non-Heap Memory（非堆内存）和Thread（线程）等。
堆内存用于存储对象实例，而非堆内存用于存储永久代（PermGen/Metaspace）等非对象实例的数据。
线程指标提供了关于应用程序当前运行的线程数的信息。
2. Heap Memory Usage (堆内存使用)Heap Memory Usage部分展示了Java应用程序堆内存的详细信息。
其中，Heap Memory Graph（堆内存图表）提供了堆内存使用量随时间的变化情况，以帮助开发人员识别内存泄漏和垃圾回收问题。
通过查看该图表，开发人员可以判断出应用程序在某个时间段内是否出现了内存占用过高的情况，并进行进一步的分析和处理。
3. Class Memory Usage (类内存使用)Class Memory Usage部分展示了Java应用程序中类的内存使用情况。
这个面板提供了一些列的图表，帮助开发人员追踪类的加载和卸载情况，以及各个类的内存占用量。
通过这些图表，开发人员可以了解哪些类占用了最多的内存，并结合代码进行优化或重构。
4. Garbage Collection (垃圾回收)Garbage Collection（垃圾回收）部分提供了对Java应用程序垃圾回收过程的监控和分析。
垃圾回收的意义英文作文
垃圾回收的意义英文作文英文：Garbage collection is an essential process in modern computing. It refers to the automatic management of memoryin a computer system. The purpose of garbage collection isto free up memory that is no longer being used by a program. This is important because if memory is not freed up, it can lead to memory leaks, which can cause a program to crash or slow down.There are several benefits of garbage collection. Oneof the main benefits is that it simplifies the programming process. When garbage collection is implemented, programmers do not have to worry about manuallydeallocating memory. This can save a lot of time and effort, especially when working on large projects.Another benefit of garbage collection is that it can improve the performance of a program. When memory ismanaged automatically, it can be more efficient than whenit is managed manually. This is because garbage collection can optimize memory usage, reduce fragmentation, andimprove locality of reference.In addition, garbage collection can also make programs more secure. When memory is not properly managed, it can be vulnerable to attacks such as buffer overflows. Garbage collection can help prevent these types of attacks by ensuring that memory is always properly allocated and deallocated.Overall, garbage collection is an important process in modern computing. It simplifies programming, improves performance, and enhances security. Without garbage collection, programs would be more difficult to develop, slower, and less secure.中文：垃圾回收是现代计算机中必不可少的过程。
捡垃圾环保英语作文初一
捡垃圾环保英语作文初一Title: The Importance of Environmental Protection Through Garbage Collection。
In today's world, environmental protection has become a pressing issue that demands our attention. One significant aspect of this endeavor is garbage collection. As a middle school student, I understand the importance of contributing to environmental conservation efforts. In this essay, Iwill delve into the significance of garbage collection in protecting our environment and discuss how individuals can play a crucial role in this process.First and foremost, garbage collection is vital for maintaining cleanliness in our surroundings. When waste is left unattended, it not only creates an eyesore but also poses health hazards. Garbage attracts pests and insects, leading to the spread of diseases. By regularly collecting and disposing of garbage properly, we can prevent these negative consequences and ensure a clean and healthyenvironment for ourselves and future generations.Moreover, proper garbage collection is essential for minimizing pollution. Improper disposal of waste, such as littering in public spaces or dumping trash into water bodies, can contaminate the environment and harm wildlife. Plastics, in particular, pose a significant threat to marine life, as they can take hundreds of years to decompose and often end up in the oceans, endangering marine ecosystems. Through responsible garbage collection practices, we can reduce pollution and mitigate its adverse effects on the environment.Furthermore, garbage collection plays a crucial role in waste management and recycling. Many items that end up in the trash can actually be recycled or repurposed, reducing the strain on natural resources and energy consumption. By separating recyclable materials from non-recyclables and disposing of them accordingly, we can contribute to the conservation of resources and the reduction of greenhouse gas emissions associated with waste disposal.As individuals, we can actively participate in garbage collection efforts in several ways. Firstly, we can start by reducing our own waste generation through practices such as using reusable items, avoiding single-use plastics, and composting organic waste. Additionally, we can participate in community clean-up events and volunteer for local environmental organizations dedicated to waste management and conservation. By raising awareness about the importance of garbage collection and leading by example, we caninspire others to join us in protecting the environment.In conclusion, garbage collection plays a crucial role in environmental protection by maintaining cleanliness, minimizing pollution, and promoting waste management and recycling. As individuals, we have a responsibility to contribute to these efforts by adopting responsible waste disposal practices and actively participating in garbage collection initiatives. By working together, we can create a cleaner, healthier, and more sustainable environment for all.。
垃圾回收利用英文作文
垃圾回收利用英文作文英文：Garbage collection is a crucial process in managing computer memory. It involves identifying and freeing up memory that is no longer being used by a program. There are two main types of garbage collection: automatic and manual.Automatic garbage collection is the most common method used today. It works by periodically scanning thecomputer's memory for objects that are no longer being used. Once these objects are identified, the garbage collector frees up the memory they were using. This process is repeated at regular intervals to ensure that memory is always being efficiently used.Manual garbage collection, on the other hand, requires the programmer to manually identify and free up memory that is no longer being used. This can be a time-consuming and error-prone process, which is why automatic garbagecollection is preferred.One of the benefits of garbage collection is that it helps to prevent memory leaks. A memory leak occurs when a program fails to release memory that is no longer being used. Over time, this can cause the program to consume more and more memory, eventually leading to a crash.Another benefit of garbage collection is that it makes programming easier. By automating the process of memory management, programmers can focus on writing code instead of worrying about memory allocation and deallocation.Overall, garbage collection is an important process in managing computer memory. It helps to prevent memory leaks and makes programming easier.中文：垃圾回收是管理计算机内存的关键过程。
python垃圾回收机制（Garbagecollection）
python垃圾回收机制（Garbagecollection） 由于⾯试中遇到了垃圾回收的问题，转载学习和总结这个问题。
在C/C++中采⽤⽤户⾃⼰管理维护内存的⽅式。
⾃⼰管理内存极其⾃由，可以任意申请内存，但也为⼤量内存泄露、悬空指针等bug埋下隐患。
因此在现在的⾼级语⾔（java、C#等）都采⽤了垃圾收集机制。
python也采⽤了垃圾收集机制，采⽤引⽤计算机制为主，标记——清除和分代收集两种机制为辅的策略。
⼀、引⽤计数机制 python⾥每⼀个东西都是对象，它们的核⼼就是⼀个结构体：PyObject。
typedef struct_object {int ob_refcnt;struct_typeobject *ob_type;} PyObject; PyObject是每个对象必有的内容，其中ob_refcnt就是做为引⽤计数。
当⼀个对象有新的引⽤时，它的ob_refcnt就会增加，当引⽤它的对象被删除，它的ob_refcnt就会减少。
#define Py_INCREF(op) ((op)->ob_refcnt++) //增加计数#define Py_DECREF(op) \ //减少计数if (--(op)->ob_refcnt != 0) \; \else \__Py_Dealloc((PyObject *)(op)) 引⽤计数为0时，该对象声明就结束了。
1、引⽤计数机制优点简单实时性：⼀旦没有引⽤，内存就直接释放了。
不⽤像其他机制等到特定时机。
实时性还带来⼀个好处：处理回收内存的时间分摊到了平时2、引⽤计数机制缺点维护引⽤计数消耗资源循环引⽤list1 = []list2 = []list1.append(list2)list2.append(list1) list1与list2相互引⽤，如果不存在其他对象对它们的引⽤，list1与list2的引⽤计数也仍然为1，所占⽤的内存永远⽆法被回收，这将是致命的。
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使用 -XX:+UseParallelGC ，也是JDK5 -server的默认值。策略为：
1.年轻代暂停应用程序，多个垃圾收集线程并行的复制收集，线程数默认为CPU个数，CPU很多时，可用–XX:ParallelGCThreads=减少线程数。
2.年老代暂停应用程序，与串行收集器一样，单垃圾收集线程标记整理。
Old(Tenured) -- major colletion -- 标记清除/标记整理算法
三、收集器
Байду номын сангаас
1.古老的串行收集器(Serial Collector)
使用 -XX:+UseSerialGC，策略为年轻代串行复制，年老代串行标记整理。
2.吞吐量优先的并行收集器(Throughput Collector)
会程序运行过程中将显示如下输出
9.211: [GC 9.211: [ParNew: 7994K->0K(8128K), 0.0123935 secs] 427172K->419977K(524224K), 0.0125728 secs]
显示在程序运行的9.211秒发生了Minor的垃圾收集，前一段数据针对新生区，从7994k整理为0k，新生区总大小为8128k，程序暂停了12ms，而后一段数据针对整个堆。
System.gc()会引发major collection，使用-XX:+DisableExplicitGC禁止它，或设为CMS并发-XX:+ExplicitGCInvokesConcurrent。
5.小结
Young -- minor collection -- 复制算法
Permanent，持久代。装载Class信息等基础数据，默认64M，如果是类很多很多的服务程序，需要加大其设置-XX:MaxPermSize=，否则它满了之后会引起fullgc()或Out of Memory。 注意Spring，Hibernate这类喜欢AOP动态生成类的框架需要更多的持久代内存。
Old(Tenured)，年老代。年轻代的对象如果能够挺过数次收集，就会进入老人区。老人区使用标记整理算法。因为老人区的对象都没那么容易死的，采用复制算法就要反复的复制对象，很不合算，只好采用标记清理算法，但标记清理算法其实也不轻松，每次都要遍历区域内所有对象，所以还是没有免费的午餐啊。
-XX:MaxTenuringThreshold=设置熬过年轻代多少次收集后移入老人区，CMS中默认为0，熬过第一次GC就转入，可以用-XX:+PrintTenuringDistribution查看。
已停止维护，–Xincgc选项默认转为并发收集器。
四、暂停时间显示
加入下列参数 (请将PrintGC和Details中间的空格去掉，CSDN很怪的认为是禁止字句）
-verbose:gc -XX:+PrintGC Details -XX:+PrintGCTimeStamps
Java Tuning White Paper 官方文档。
FAQ about Garbage Collection in the Hotspot 官方FAQ，JVM1.4.2。
Java HotSpot 虚拟机中的垃圾收集 JavaOne2004上的中文ppt
A Collection of JVM Options JVM选项的超完整收集。
Young(Nursery)，年轻代。研究表明大部分对象都是朝生暮死，随生随灭的。因此所有收集器都为年轻代选择了复制算法。
复制算法优点是只访问活跃对象，缺点是复制成本高。因为年轻代只有少量的对象能熬到垃圾收集，因此只需少量的复制成本。而且复制收集器只访问活跃对象，对那些占了最大比率的死对象视而不见，充分发挥了它遍历空间成本低的优点。
所以需要2+的CPU时才会优于串行收集器，适用于后台处理，科学计算。
可以使用-XX:MaxGCPauseMillis= 和 -XX:GCTimeRatio 来调整GC的时间。
3.暂停时间优先的并发收集器(Concurrent Low Pause Collector-CMS)
Young的大小非常非常重要，见“后面暂停时间优先收集器”的论述。
Young里面又分为3个区域，一个Eden，所有新建对象都会存在于该区，两个Survivor区，用来实施复制算法。每次复制就是将Eden和第一块Survior的活对象复制到第2块，然后清空Eden与第一块Survior。Eden与Survivor的比例由-XX:SurvivorRatio=设置，默认为32。Survivio大了会浪费，小了的话，会使一些年轻对象潜逃到老人区，引起老人区的不安，但这个参数对性能并不重要。
并行(Parallel)与并发(Concurrent)仅一字之差，并行指多条垃圾收集线程并行，并发指用户线程与垃圾收集线程并发，程序在继续运行，而垃圾收集程序运行于另一个个CPU上。
并发收集一开始会很短暂的停止一次所有线程来开始初始标记根对象，然后标记线程与应用线程一起并发运行，最后又很短的暂停一次，多线程并行的重新标记之前可能因为并发而漏掉的对象，然后就开始与应用程序并发的清除过程。可见，最长的两个遍历过程都是与应用程序并发执行的，比以前的串行算法改进太多太多了！！！
因此Young的大小设置挺重要的，大点就不用频繁GC，而且增大GC的间隔后，可以让多点对象自己死掉而不用复制了。但Young增大时，GC造成的停顿时间攀升得非常恐怖，比如在我的机器上，默认8M的Young，只需要几毫秒的时间，64M就升到90毫秒，而升到256M时，就要到300毫秒了，峰值还会攀到恐怖的800ms。谁叫复制算法，要等Young满了才开始收集，开始收集就要停止所有线程呢。
一、参考资料：
Tuning Garbage Collection with the 5.0 Java Virtual Machine 官方指南。 /technetwork/java/gc-tuning-5-138395.html
Hotspot memory management whitepaper 官方白皮书。
3.2 年轻代详述
可惜对年轻代的复制收集，依然必须停止所有应用程序线程，原理如此，只能靠多CPU，多收集线程并发来提高收集速度，但除非你的Server独占整台服务器，否则如果服务器上本身还有很多其他线程时，切换起来速度就..... 所以，搞到最后，暂停时间的瓶颈就落在了年轻代的复制算法上。
标记整理(mark-sweep-compact)：综合了上述两者的做法和优点，先标记活跃对象，然后将其合并成较大的内存块。
可见，没有免费的午餐，无论采用复制还是标记清除算法，自动的东西都要付出很大的性能代价。
3.分代
分代是Java垃圾收集的一大亮点，根据对象的生命周期长短，把堆分为3个代：Young，Old和Permanent，根据不同代的特点采用不同的收集算法，扬长避短也。
前面说了这么多，都是为了这节做铺垫......
使用-XX:+UseConcMarkSweepGC，策略为：
1.年轻代同样是暂停应用程序，多个垃圾收集线程并行的复制收集。
2.年老代则只有两次短暂停，其他时间应用程序与收集线程并发的清除。
3.1 年老代详述
因为只访问活跃对象，将所有活动对象复制走之后就清空整个空间，不用去访问死对象，所以遍历空间的成本较小，但需要巨大的复制成本和较多的内存。
标记清除(mark-sweep)：收集器先从根开始访问所有活跃对象，标记为活跃对象。然后再遍历一次整个内存区域，把所有没有标记活跃的对象进行回收处理。该算法遍历整个空间的成本较大暂停时间随空间大小线性增大，而且整理后堆里的碎片很多。
再加两个参数 -XX:+PrintGCApplicationConcurrentTime -XX:+PrintGCApplicationStoppedTime对暂停时间看得更清晰。
五、真正不停的BEA JRockit 与Sun RTS2.0
Bea的JRockit 5.0 R27 的特色之一是动态决定的垃圾收集策略，用户可以决定自己关心的是吞吐量，暂停时间还是确定的暂停时间，再由JVM在运行时动态决定、改变改变垃圾收集策略。
Young的默认值为4M，随堆内存增大，约为1/15，JVM会根据情况动态管理其大小变化。
-XX:NewRatio= 参数可以设置Young与Old的大小比例，-server时默认为1:2，但实际上young启动时远低于这个比率？如果信不过JVM，也可以用-Xmn硬性规定其大小，有文档推荐设为Heap总大小的1/4。
3.3 持久代
可设置-XX:+CMSClassUnloadingEnabled
-XX:+CMSPermGenSweepingEnabled，使CMS收集持久代的类，而不是fullgc，netbeans5.5 performance文档的推荐。
4.增量(train算法)收集器(Incremental Collector)
默认空余堆内存大于70%时，JVM会减少堆直到-Xms的最小限制，可以由-XX:MaxHeapFreeRatio=指定。
服务器一般设置-Xms、-Xmx相等以避免在每次GC 后调整堆的大小，所以上面的两个参数没啥用。
2.基本收集算法
复制：将堆内分成两个相同空间，从根(ThreadLocal的对象，静态对象）开始访问每一个关联的活跃对象，将空间A的活跃对象全部复制到空间B，然后一次性回收整个空间A。
它的Deterministic GC的选项是-Xgcprio: deterministic，号称可以把暂停可以控制在10-30毫秒，非常的牛，一句Deterministic道尽了RealTime的真谛。 不过细看一下文档，30ms的测试环境是1 GB heap 和 平均 30% 的活跃对象(也就是300M)活动对象，2 个 Xeon 3.6 GHz 4G内存 ，或者是4 个Xeon 2.0 GHz，8G内存。